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Superconductivity In Fese
Title
Superconductivity In Fese: The Role Of Nematic Order.
Creator
Kang, Jian, Fernandes, Rafael M., Chubukov, Andrey
Abstract/Description
Bulk FeSe is a special iron-based material in which superconductivity emerges inside a well-developed nematic phase. We present a microscopic model for this nematic superconducting state, which takes into account the mixing between s-wave and d-wave pairing channels and the changes in the orbital spectral weight promoted by the sign-changing nematic order parameter. We show that nematicity only weakly affects T-c, but gives rise to cos 2 theta variation of the pairing gap on the hole pocket,...
Show moreBulk FeSe is a special iron-based material in which superconductivity emerges inside a well-developed nematic phase. We present a microscopic model for this nematic superconducting state, which takes into account the mixing between s-wave and d-wave pairing channels and the changes in the orbital spectral weight promoted by the sign-changing nematic order parameter. We show that nematicity only weakly affects T-c, but gives rise to cos 2 theta variation of the pairing gap on the hole pocket, whose magnitude and size agrees with angle resolved photoemission spectroscopy and STM data. We further show that nematicity increases the weight of the d(xz) orbital on the hole pocket, and increases (reduces) the weight of the d(xy), orbital on the Y (X) electron pocket.
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Date Issued
2018-06-26
Identifier
FSU_libsubv1_wos_000436558800006, 10.1103/PhysRevLett.120.267001
Format
Citation
Collective Dynamics And Strong Pinning Near The Onset Of Charge Order In La1.48nd0.4sr0.12cuo4
Title
Collective Dynamics And Strong Pinning Near The Onset Of Charge Order In La1.48nd0.4sr0.12cuo4.
Creator
Baity, P. G., Sasagawa, T., Popovic, Dragana
Abstract/Description
The dynamics of charge-ordered states is one of the key issues in underdoped cuprate high-temperature superconductors, but static short-range charge-order (CO) domains have been detected in almost all cuprates. We probe the dynamics across the CO (and structural) transition in La1.48Nd0.4Sr0.12CuO4 by measuring nonequilibrium charge transport, or resistance R as the system responds to a change in temperature and to an applied magnetic field. We find evidence for metastable states, collective...
Show moreThe dynamics of charge-ordered states is one of the key issues in underdoped cuprate high-temperature superconductors, but static short-range charge-order (CO) domains have been detected in almost all cuprates. We probe the dynamics across the CO (and structural) transition in La1.48Nd0.4Sr0.12CuO4 by measuring nonequilibrium charge transport, or resistance R as the system responds to a change in temperature and to an applied magnetic field. We find evidence for metastable states, collective behavior, and criticality. The collective dynamics in the critical regime indicates strong pinning by disorder. Surprisingly, nonequilibrium effects, such as avalanches in R, are revealed only when the critical region is approached from the charge-ordered phase. Our results on La1.48Nd0.4Sr0.12CuO4 provide the long-sought evidence for the fluctuating order across the CO transition, and also set important constraints on theories of dynamic stripes.
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Date Issued
2018-04-12
Identifier
FSU_libsubv1_wos_000429777200009, 10.1103/PhysRevLett.120.156602
Format
Citation
Isotensor Dibaryon In The Pp -> Pp Pi(+)pi(-) Reaction?
Title
Isotensor Dibaryon In The Pp -> Pp Pi(+)pi(-) Reaction?.
Creator
Adlarson, P., Augustyniak, W., Bardan, W., Bashkanov, M., Bergmann, F. S., Berlowski, M., Bondar, A., Buescher, M., Calen, H., Ciepal, I., Clement, H., Czerwinski, E., Demmich,...
Show moreAdlarson, P., Augustyniak, W., Bardan, W., Bashkanov, M., Bergmann, F. S., Berlowski, M., Bondar, A., Buescher, M., Calen, H., Ciepal, I., Clement, H., Czerwinski, E., Demmich, K., Engels, R., Erven, A., Erven, W., Eyrich, W., Fedorets, P., Foehl, K., Fransson, K., Goldenbaum, F., Goswami, A., Grigoryev, K., Heijkenskjold, L., Hejny, V., Huesken, N., Jarczyk, L., Johansson, T., Kamys, B., Kemmerling, G., Khoukaz, A., Khreptak, O., Kirillov, D. A., Kistryn, S., Kleines, H., Klos, B., Krzemien, W., Kulessa, P., Kupsc, A., Lalwani, K., Lersch, D., Lorentz, B., Magiera, A., Maier, R., Marciniewski, P., Marianski, B., Morsch, H. P., Moskal, P., Ohm, H., Parol, W., del Rio, E. Perez, Piskunov, N. M., Prasuhn, D., Pszczel, D., Pysz, K., Ritman, J., Roy, A., Rudy, Z., Rundel, O., Sawant, S., Schadmand, S., Schatti-Ozerianska, I., Sefzick, T., Serdyuk, V., Shwartz, B., Skorodko, T., Skurzok, M., Smyrski, J., Sopov, V., Stassen, R., Stepaniak, J., Stephan, E., Sterzenbach, G., Stockhorst, H., Stroeher, H., Szczurek, A., Trzcinski, A., Wolke, M., Wronska, A., Wuestner, P., Yamamoto, A., Zabierowski, J., Zielinski, M. J., Zlomanczuk, J., Zupranski, P., Zurek, M.
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Abstract/Description
Exclusive measurements of the quasifree pp -> pp pi(+)pi(-) reaction have been carried out at WASA@ COSY by means of pd collisions at T-p = 1.2 GeV. Total and differential cross sections have been extracted covering the energy region T-p = 1.08-1.36 GeV, which is the region of N* (1440) and Delta(123)Delta(1232) resonance excitations. Calculations describing these excitations by t-channel meson exchange are at variance with the measured differential cross sections and underpredict...
Show moreExclusive measurements of the quasifree pp -> pp pi(+)pi(-) reaction have been carried out at WASA@ COSY by means of pd collisions at T-p = 1.2 GeV. Total and differential cross sections have been extracted covering the energy region T-p = 1.08-1.36 GeV, which is the region of N* (1440) and Delta(123)Delta(1232) resonance excitations. Calculations describing these excitations by t-channel meson exchange are at variance with the measured differential cross sections and underpredict substantially the experimental total cross section. An isotensor Delta N dibaryon resonance with I(J(P)) = 2(1(+)) produced associatedly with a pion is able to overcome these deficiencies.
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Date Issued
2018-08-01
Identifier
FSU_libsubv1_wos_000440415600003, 10.1103/PhysRevLett.121.052001
Format
Citation
Low-energy Excitations In Quantum Spin Liquids Identified By Optical Spectroscopy
Title
Low-energy Excitations In Quantum Spin Liquids Identified By Optical Spectroscopy.
Creator
Pustogow, A., Saito, Y., Zhukova, E., Gorshunov, B., Kato, R., Lee, T.-H., Fratini, S., Dobrosavljevic, V., Dressel, M.
Abstract/Description
The electrodynamic response of organic spin liquids with highly frustrated triangular lattices has been measured in a wide energy range. While the overall optical spectra of these Mott insulators are governed by transitions between the Hubbard bands, distinct in-gap excitations can be identified at low temperatures and frequencies, which we attribute to the quantum-spin-liquid state. For the strongly correlated ss'-EtMe3Sb[Pd(dmit)(2)](2), we discover enhanced conductivity below 175 cm(-1),...
Show moreThe electrodynamic response of organic spin liquids with highly frustrated triangular lattices has been measured in a wide energy range. While the overall optical spectra of these Mott insulators are governed by transitions between the Hubbard bands, distinct in-gap excitations can be identified at low temperatures and frequencies, which we attribute to the quantum-spin-liquid state. For the strongly correlated ss'-EtMe3Sb[Pd(dmit)(2)](2), we discover enhanced conductivity below 175 cm(-1), comparable to the energy of the magnetic coupling J approximate to 250 K. For omega -> 0, these low-frequency excitations vanish faster than the charge-carrier response subject to Mott-Hubbard correlations, resulting in a dome-shaped band peaked at 100 cm(-1). Possible relations to spinons, magnons, and disorder are discussed.
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Date Issued
2018-08-03
Identifier
FSU_libsubv1_wos_000440724200014, 10.1103/PhysRevLett.121.056402
Format
Citation
Giant Pressure Dependence And Dimensionality Switching In A Metal-organic Quantum Antiferromagnet
Title
Giant Pressure Dependence And Dimensionality Switching In A Metal-organic Quantum Antiferromagnet.
Creator
Wehinger, B., Fiolka, C., Lanza, A., Scatena, R., Kubus, M., Grockowiak, A., Coniglio, W. A., Graf, D., Skoulatos, M., Chen, J.-H., Gukelberger, J., Casati, N., Zaharko, O.,...
Show moreWehinger, B., Fiolka, C., Lanza, A., Scatena, R., Kubus, M., Grockowiak, A., Coniglio, W. A., Graf, D., Skoulatos, M., Chen, J.-H., Gukelberger, J., Casati, N., Zaharko, O., Macchi, P., Kramer, K. W., Tozer, S., Mudry, C., Normand, B., Ruegg, Ch
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Abstract/Description
We report an extraordinary pressure dependence of the magnetic interactions in the metal-organic system [CuF2(H2O)(2)](2) pyrazine. At zero pressure, this material realizes a quasi-two-dimensional spin-1/2 squarelattice Heisenberg antiferromagnet. By high-pressure, high-field susceptibility measurements we show that the dominant exchange parameter is reduced continuously by a factor of 2 on compression. Above 18 kbar, a phase transition occurs, inducing an orbital re-ordering that switches...
Show moreWe report an extraordinary pressure dependence of the magnetic interactions in the metal-organic system [CuF2(H2O)(2)](2) pyrazine. At zero pressure, this material realizes a quasi-two-dimensional spin-1/2 squarelattice Heisenberg antiferromagnet. By high-pressure, high-field susceptibility measurements we show that the dominant exchange parameter is reduced continuously by a factor of 2 on compression. Above 18 kbar, a phase transition occurs, inducing an orbital re-ordering that switches the dimensionality, transforming the quasi-two-dimensional lattice into weakly coupled chains. We explain the microscopic mechanisms for both phenomena by combining detailed x-ray and neutron diffraction studies with quantitative modeling using spin-polarized density functional theory.
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Date Issued
2018-09-11
Identifier
FSU_libsubv1_wos_000444586600017, 10.1103/PhysRevLett.121.117201
Format
Citation
Evidence For Ferromagnetic Clusters In The Colossal-magnetoresistance Material Eub6
Title
Evidence For Ferromagnetic Clusters In The Colossal-magnetoresistance Material Eub6.
Creator
Pohlit, Merlin, Roessler, Sahana, Ohno, Yuzo, Ohno, Hideo, von Molnar, Stephan, Fisk, Zachary, Mueller, Jens, Wirth, Steffen
Abstract/Description
We combined scanning tunneling microscopy and locally resolved magnetic stray field measurements on the ferromagnetic semimetal EuB6, which exhibits a complex ferromagnetic order and a colossal magnetoresistance effect. In a zero magnetic field, scanning tunneling spectroscopy visualizes the existence of local inhomogeneities in the electronic density of states, which we interpret as the localization of charge carriers due to the formation of magnetic polarons. Micro-Hall magnetometry...
Show moreWe combined scanning tunneling microscopy and locally resolved magnetic stray field measurements on the ferromagnetic semimetal EuB6, which exhibits a complex ferromagnetic order and a colossal magnetoresistance effect. In a zero magnetic field, scanning tunneling spectroscopy visualizes the existence of local inhomogeneities in the electronic density of states, which we interpret as the localization of charge carriers due to the formation of magnetic polarons. Micro-Hall magnetometry measurements of the total stray field emanating from the end of a rectangular-shaped platelike sample reveals evidence for magnetic clusters also in finite magnetic fields. In contrast, the signal detected below the faces of the magnetized sample measures a local stray field indicating the formation of pronounced magnetic inhomogeneities consistent with large clusters of percolated magnetic polarons.
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Date Issued
2018-06-19
Identifier
FSU_libsubv1_wos_000435551200004, 10.1103/PhysRevLett.120.257201
Format
Citation
Neutron Skins And Neutron Stars In The Multimessenger Era
Title
Neutron Skins And Neutron Stars In The Multimessenger Era.
Creator
Fattoyev, F. J., Piekarewicz, J., Horowitz, C. J.
Abstract/Description
The historical first detection of a binary neutron star merger by the LIGO-Virgo Collaboration [B. P. Abbott et al., Phys. Rev. Lett. 119, 161101 (2017)] is providing fundamental new insights into the astrophysical site for the r process and on the nature of dense matter. A set of realistic models of the equation of state (EOS) that yield an accurate description of the properties of finite nuclei, support neutron stars of two solar masses, and provide a Lorentz covariant extrapolation to...
Show moreThe historical first detection of a binary neutron star merger by the LIGO-Virgo Collaboration [B. P. Abbott et al., Phys. Rev. Lett. 119, 161101 (2017)] is providing fundamental new insights into the astrophysical site for the r process and on the nature of dense matter. A set of realistic models of the equation of state (EOS) that yield an accurate description of the properties of finite nuclei, support neutron stars of two solar masses, and provide a Lorentz covariant extrapolation to dense matter are used to confront its predictions against tidal polarizabilities extracted from the gravitational-wave data. Given the sensitivity of the gravitational-wave signal to the underlying EOS, limits on the tidal polarizability inferred from the observation translate into constraints on the neutron-star radius. Based on these constraints, models that predict a stiff symmetry energy, and thus large stellar radii, can be ruled out. Indeed, we deduce an upper limit on the radius of a 1.4M circle dot neutron star of R1.4. < 13.76 km. Given the sensitivity of the neutron-skin thickness of Pb-208 to the symmetry energy, albeit at a lower density, we infer a corresponding upper limit of about R-skin(208) less than or similar to 0.25 fm. However, if the upcoming PREX-II experiment measures a significantly thicker skin, this may be evidence of a softening of the symmetry energy at high densities-likely indicative of a phase transition in the interior of neutron stars.
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Date Issued
2018-04-25
Identifier
FSU_libsubv1_wos_000430822000003, 10.1103/PhysRevLett.120.172702
Format
Citation
Bulk Fermi Surfaces Of The Dirac Type-ii Semimetallic Candidates Mal3 (where M = V, Nb, And Ta)
Title
Bulk Fermi Surfaces Of The Dirac Type-ii Semimetallic Candidates Mal3 (where M = V, Nb, And Ta).
Creator
Chen, K.-W., Lian, X., Lai, Y., Aryal, N., Chiu, Y.-C., Lan, W., Graf, D., Manousakis, E., Baumbach, R. E., Balicas, L.
Abstract/Description
We report a de Haas-van Alphen (dHvA) effect study on the Dirac type-II semimetallic candidates MAl3 (where, M = V, Nb and Ta). The angular dependence of their Fermi surface (FS) cross-sectional areas reveals a remarkably good agreement with our first-principles calculations. Therefore, dHvA supports the existence of tilted Dirac cones with Dirac type-II nodes located at 100, 230 and 250 meV above the Fermi level epsilon(F) for VAl3 , NbAl3 and TaAl3 respectively, in agreement with the...
Show moreWe report a de Haas-van Alphen (dHvA) effect study on the Dirac type-II semimetallic candidates MAl3 (where, M = V, Nb and Ta). The angular dependence of their Fermi surface (FS) cross-sectional areas reveals a remarkably good agreement with our first-principles calculations. Therefore, dHvA supports the existence of tilted Dirac cones with Dirac type-II nodes located at 100, 230 and 250 meV above the Fermi level epsilon(F) for VAl3 , NbAl3 and TaAl3 respectively, in agreement with the prediction of broken Lorentz invariance in these compounds. However, for all three compounds we find that the cyclotron orbits on their FSs, including an orbit nearly enclosing the Dirac type-II node, yield trivial Berry phases. We explain this via an analysis of the Berry phase where the position of this orbit, relative to the Dirac node, is adjusted within the error implied by the small disagreement between our calculations and the experiments. We suggest that a very small amount of doping could displace epsilon(F) to produce topologically nontrivial orbits encircling their Dirac node(s).
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Date Issued
2018-05-15
Identifier
FSU_libsubv1_wos_000433030700009, 10.1103/PhysRevLett.120.206401
Format
Citation
Center Of Mass Motion Of Short-range Correlated Nucleon Pairs Studied Via The A(e,e ' Pp) Reaction
Title
Center Of Mass Motion Of Short-range Correlated Nucleon Pairs Studied Via The A(e,e ' Pp) Reaction.
Creator
Cohen, E. O., Hen, O., Piasetzky, E., Weinstein, L. B., Duer, M., Schmidt, A., Korover, I., Hakobyan, H., Adhikari, S., Akbar, Z., Amaryan, M. J., Avakian, H., Ball, J., Barion,...
Show moreCohen, E. O., Hen, O., Piasetzky, E., Weinstein, L. B., Duer, M., Schmidt, A., Korover, I., Hakobyan, H., Adhikari, S., Akbar, Z., Amaryan, M. J., Avakian, H., Ball, J., Barion, L., Battaglieri, M., Beck, A., Bedlinskiy, I., Biselli, A. S., Boiarinov, S., Briscoe, W., Burkert, V. D., Cao, F., Carman, D. S., Celentano, A., Charles, G., Chatagnon, Pierre, Chetry, T., Ciullo, G., Clary, Brandon A., Contalbrigo, M., Crede, V., Torres, R. Cruz, D'Angelo, A., Dashyan, N., De Vita, R., De Sanctis, E., Defurne, M., Deur, A., Diehl, S., Djalali, C., Duer, M., Dupre, R., Egiyan, H., Ehrhart, Mathieu, El Alaoui, A., El Fassi, L., Eugenio, P., Fedotov, G., Fersch, R., Filippi, A., Ghandilyan, Y., Giovanetti, K. L., Girod, F. X., Golovatch, E., Gothe, R. W., Griffioen, K. A., Hafidi, K., Harrison, N., Hauenstein, F., Heddle, D., Hicks, K., Holtrop, M., Ireland, D. G., Ishkhanov, B. S., Isupov, E. L., Jenkins, D., Jo, H. S., Johnston, S., Kabir, M. L., Keller, D., Khachatryan, G., Khachatryan, M., Khandaker, M., Kim, A., Kim, W., Klein, A., Klein, F. J., Korover, I., Kubarovsky, V., Kuhn, S. E., Lanza, L., Lenisa, P., Livingston, K., MacGregor, I. J. D., Marchand, D., McKinnon, B., Beck, S. Mey-Tal, Meyer, C. A., Mirazita, M., Mokeev, V., Montgomery, R. A., Movsisyan, A., Camacho, C. Munoz, Mustapha, B., Nadel-Turonski, P., Niccolai, S., Niculescu, G., Osipenko, M., Ostrovidov, A. I., Paolone, M., Paremuzyan, R., Pasyuk, E., Pogorelko, O., Price, J. W., Prok, Y., Protopopescu, D., Ripani, M., Riser, D., Rizzo, A., Rosner, G., Rossi, P., Sabatie, F., Schmookler, B. A., Schumacher, R. A., Sharabian, Y. G., Sokhan, D., Sparveris, N., Stepanyan, S., Strauch, S., Taiuti, M., Tan, J. A., Ungaro, M., Voskanyan, H., Voutier, E., Wang, R., Watts, D. P., Wei, X., Wood, M. H., Zachariou, N., Zhang, J., Zheng, X., Zhao, Z. W.
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Abstract/Description
Short-range correlated (SRC) nucleon pairs are a vital part of the nucleus, accounting for almost all nucleons with momentum greater than the Fermi momentum (k(F)). A fundamental characteristic of SRC pairs is having large relative momenta as compared to k(F), and smaller center of mass (c.m.) which indicates a small separation distance between the nucleons in the pair. Determining the c.m. momentum distribution of SRC pairs is essential for understanding their formation process. We report...
Show moreShort-range correlated (SRC) nucleon pairs are a vital part of the nucleus, accounting for almost all nucleons with momentum greater than the Fermi momentum (k(F)). A fundamental characteristic of SRC pairs is having large relative momenta as compared to k(F), and smaller center of mass (c.m.) which indicates a small separation distance between the nucleons in the pair. Determining the c.m. momentum distribution of SRC pairs is essential for understanding their formation process. We report here on the extraction of the c.m. motion of proton-proton (pp) SRC pairs in carbon and, for the first time in heavier and ansymetric nuclei: aluminum, iron, and lead, from measurements of the A(e,e'pp) reaction. We find that the pair c.m. motion for these nuclei can be described by a three-dimensional Gaussian with a narrow width ranging from 140 to 170 MeV/c, approximately consistent with the sum of two mean-field nucleon momenta. Comparison with calculations appears to show that the SRC pairs are formed from mean-field nucleons in specific quantum states.
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Date Issued
2018-08-31
Identifier
FSU_libsubv1_wos_000443408500009, 10.1103/PhysRevLett.121.092501
Format
Citation
Evidence of Topological Nodal-Line Fermions in ZrSiSe and ZrSiTe
Title
Evidence Of Topological Nodal-line Fermions In Zrsise And Zrsite.
Creator
Hu, Jin, Tang, Zhijie, Liu, Jinyu, Liu, Xue, Zhu, Yanglin, Graf, David, Myhro, Kevin, Tran, Son, Lau, Chun Ning, Wei, Jiang, Mao, Zhiqiang
Abstract/Description
A Dirac nodal-line semimetal phase, which represents a new quantum state of topological materials, has been experimentally realized only in a few systems, including PbTaSe2, PtSn4, and ZrSiS. In this Letter, we report evidence of nodal-line fermions in ZrSiSe and ZrSiTe probed in de Haas-van Alphen quantum oscillations. Although ZrSiSe and ZrSiTe share a similar layered structure with ZrSiS, our studies show the Fermi surface (FS) enclosing a Dirac nodal line has a 2D character in ZrSiTe, in...
Show moreA Dirac nodal-line semimetal phase, which represents a new quantum state of topological materials, has been experimentally realized only in a few systems, including PbTaSe2, PtSn4, and ZrSiS. In this Letter, we report evidence of nodal-line fermions in ZrSiSe and ZrSiTe probed in de Haas-van Alphen quantum oscillations. Although ZrSiSe and ZrSiTe share a similar layered structure with ZrSiS, our studies show the Fermi surface (FS) enclosing a Dirac nodal line has a 2D character in ZrSiTe, in contrast with 3D-like FS in ZrSiSe and ZrSiS. Another important property revealed in our experiment is that the nodal-line fermion density in this family of materials (similar to 10(20) cm(-3)) is much higher than the Dirac fermion density of other topological materials with discrete nodes. In addition, we have demonstrated ZrSiSe and ZrSiTe single crystals can be thinned down to 2D atomic thin layers through microexfoliation, which offers the first platform to explore exotic properties of topological nodal-line fermions in low dimensions.
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Date Issued
2016-06-30
Identifier
FSU_libsubv1_wos_000378881300009, 10.1103/PhysRevLett.117.016602
Format
Citation
Fractional Quantum Hall States in a Ge Quantum Well
Title
Fractional Quantum Hall States in a Ge Quantum Well.
Creator
Mironov, O. A., d'Ambrumenil, N., Dobbie, A., Leadley, D. R., Suslov, A. V., Green, E.
Abstract/Description
Measurements of the Hall and dissipative conductivity of a strained Ge quantum well on a SiGe/(001)Si substrate in the quantum Hall regime are reported. We analyze the results in terms of thermally activated quantum tunneling of carriers from one internal edge state to another across saddle points in the long-range impurity potential. This shows that the gaps for different filling fractions closely follow the dependence predicted by theory. We also find that the estimates of the separation of...
Show moreMeasurements of the Hall and dissipative conductivity of a strained Ge quantum well on a SiGe/(001)Si substrate in the quantum Hall regime are reported. We analyze the results in terms of thermally activated quantum tunneling of carriers from one internal edge state to another across saddle points in the long-range impurity potential. This shows that the gaps for different filling fractions closely follow the dependence predicted by theory. We also find that the estimates of the separation of the edge states at the saddle are in line with the expectations of an electrostatic model in the lowest spin-polarized Landau level (LL), but not in the spin-reversed LL where the density of quasiparticle states is not high enough to accommodate the carriers required.
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Date Issued
2016-04-27
Identifier
FSU_libsubv1_wos_000374964400011, 10.1103/PhysRevLett.116.176802
Format
Citation
First-principles-based Method For Electron Localization
Title
First-principles-based Method For Electron Localization: Application To Monolayer Hexagonal Boron Nitride.
Creator
Ekuma, C. E., Dobrosavljevic, V., Gunlycke, D.
Abstract/Description
We present a first-principles-based many-body typical medium dynamical cluster approximation and density function theory method for characterizing electron localization in disordered structures. This method applied to monolayer hexagonal boron nitride shows that the presence of boron vacancies could turn this wide-gap insulator into a correlated metal. Depending on the strength of the electron interactions, these calculations suggest that conduction could be obtained at a boron vacancy...
Show moreWe present a first-principles-based many-body typical medium dynamical cluster approximation and density function theory method for characterizing electron localization in disordered structures. This method applied to monolayer hexagonal boron nitride shows that the presence of boron vacancies could turn this wide-gap insulator into a correlated metal. Depending on the strength of the electron interactions, these calculations suggest that conduction could be obtained at a boron vacancy concentration as low as 1.0%. We also explore the distribution of the local density of states, a fingerprint of spatial variations, which allows localized and delocalized states to be distinguished. The presented method enables the study of disorder-driven insulator-metal transitions not only in h-BN but also in other physical materials.
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Date Issued
2017-03-10
Identifier
FSU_libsubv1_wos_000396047700006, 10.1103/PhysRevLett.118.106404
Format
Citation
Fate of Spinons at the Mott Point
Title
Fate Of Spinons At The Mott Point.
Creator
Lee, Tsung-Han, Florens, Serge, Dobrosavljevic, Vladimir
Abstract/Description
Gapless spin liquids have recently been observed in several frustrated Mott insulators, with elementary spin excitations-"spinons"-reminiscent of degenerate Fermi systems. However, their precise role at the Mott point, where charge fluctuations begin to proliferate, remains controversial and ill understood. Here we present the simplest theoretical framework that treats the dynamics of emergent spin and charge excitations on the same footing, providing a new physical picture of the Mott metal...
Show moreGapless spin liquids have recently been observed in several frustrated Mott insulators, with elementary spin excitations-"spinons"-reminiscent of degenerate Fermi systems. However, their precise role at the Mott point, where charge fluctuations begin to proliferate, remains controversial and ill understood. Here we present the simplest theoretical framework that treats the dynamics of emergent spin and charge excitations on the same footing, providing a new physical picture of the Mott metal-to-insulator transition at half filing. We identify a generic orthogonality mechanism leading to strong damping of spinons, arising as soon as the Mott gap closes. Our results indicate that spinons should not play a significant role within the high-temperature quantum critical regime above the Mott point-in striking agreement with all available experiments.
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Date Issued
2016-09-20
Identifier
FSU_libsubv1_wos_000383849400011, 10.1103/PhysRevLett.117.136601
Format
Citation
Magnetoelectric Coupling through the Spin Flop Transition in Ni3TeO6
Title
Magnetoelectric Coupling Through The Spin Flop Transition In Ni3teo6.
Creator
Yokosuk, M. O., al-Wahish, Amal, Artyukhin, Sergey, O'Neal, K. R., Mazumdar, D., Chen, P., Yang, Junjie, Oh, Yoon Seok, McGill, Stephen A., Haule, K., Cheong, Sang-Wook,...
Show moreYokosuk, M. O., al-Wahish, Amal, Artyukhin, Sergey, O'Neal, K. R., Mazumdar, D., Chen, P., Yang, Junjie, Oh, Yoon Seok, McGill, Stephen A., Haule, K., Cheong, Sang-Wook, Vanderbilt, David, Musfeldt, J. L.
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Abstract/Description
We combined high field optical spectroscopy and first principles calculations to analyze the electronic structure of Ni3TeO6 across the 53 K and 9 T magnetic transitions, both of which are accompanied by large changes in electric polarization. The color properties are sensitive to magnetic order due to field-induced changes in the crystal field environment, with those around Ni1 and Ni2 most affected. These findings advance the understanding of magnetoelectric coupling in materials in which...
Show moreWe combined high field optical spectroscopy and first principles calculations to analyze the electronic structure of Ni3TeO6 across the 53 K and 9 T magnetic transitions, both of which are accompanied by large changes in electric polarization. The color properties are sensitive to magnetic order due to field-induced changes in the crystal field environment, with those around Ni1 and Ni2 most affected. These findings advance the understanding of magnetoelectric coupling in materials in which magnetic 3d centers coexist with nonmagnetic heavy chalcogenide cations.
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Date Issued
2016-09-30
Identifier
FSU_libsubv1_wos_000385971800013, 10.1103/PhysRevLett.117.147402
Format
Citation
Magnetic Ground States of the Rare-Earth Tripod Kagome Lattice Mg2RE3Sb3O14 (RE = Gd,Dy,Er)
Title
Magnetic Ground States of the Rare-Earth Tripod Kagome Lattice Mg2RE3Sb3O14 (RE = Gd,Dy,Er).
Creator
Dun, Z. L., Trinh, J., Li, K., Lee, M., Chen, K. W., Baumbach, R., Hu, Y. F., Wang, Y. X., Choi, E. S., Shastry, B. S., Ramirez, A. P., Zhou, H. D.
Abstract/Description
We present the structural and magnetic properties of a new compound family, Mg2RE3Sb3O14 (RE = Gd, Dy, Er), with a hitherto unstudied frustrating lattice, the "tripod kagome" structure. Susceptibility (ac, dc) and specific heat exhibit features that are understood within a simple Luttinger-Tisza-type theory. For RE = Gd, we found long-ranged order (LRO) at 1.65 K, which is consistent with a 120 degrees structure, demonstrating the importance of diople interactions for this 2D Heisenberg...
Show moreWe present the structural and magnetic properties of a new compound family, Mg2RE3Sb3O14 (RE = Gd, Dy, Er), with a hitherto unstudied frustrating lattice, the "tripod kagome" structure. Susceptibility (ac, dc) and specific heat exhibit features that are understood within a simple Luttinger-Tisza-type theory. For RE = Gd, we found long-ranged order (LRO) at 1.65 K, which is consistent with a 120 degrees structure, demonstrating the importance of diople interactions for this 2D Heisenberg system. For RE = Dy, LRO at 0.37 K is related to the "kagome spin ice" physics for a 2D system. This result shows that the tripod kagome structure accelerates the transition to LRO predicted for the related pyrochlore systems. For RE = Er, two transitions, at 80 mK and 2.1 K are observed, suggesting the importance of quantum fluctuations for this putative XY system.
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Date Issued
2016-04-12
Identifier
FSU_libsubv1_wos_000373773600014, 10.1103/PhysRevLett.116.157201
Format
Citation
Measurement Of The Q(2) Dependence Of The Deuteron Spin Structure Function G(1) And Its Moments At Low Q(2) With Clas
Title
Measurement Of The Q(2) Dependence Of The Deuteron Spin Structure Function G(1) And Its Moments At Low Q(2) With Clas.
Creator
Adhikari, K. P., Deur, A., El Fassi, L., Kang, H., Kuhn, S. E., Ripani, M., Slifer, K., Zheng, X., Adhikari, S., Akbar, Z., Amaryan, M. J., Avakian, H., Ball, J., Balossino, I.,...
Show moreAdhikari, K. P., Deur, A., El Fassi, L., Kang, H., Kuhn, S. E., Ripani, M., Slifer, K., Zheng, X., Adhikari, S., Akbar, Z., Amaryan, M. J., Avakian, H., Ball, J., Balossino, I., Barion, L., Battaglieri, M., Bedlinskiy, I., Biselli, A. S., Bosted, P., Briscoe, W. J., Brock, J., Bultmann, S., Burkert, V. D., Cao, F. Thanh, Carlin, C., Carman, D. S., Celentano, A., Charles, G., Chen, J.-P., Chetry, T., Choi, S., Ciullo, G., Clark, L., Cole, P. L., Contalbrigo, M., Crede, V., D'Angelo, A., Dashyan, N., De Vita, R., De Sanctis, E., Defurne, M., Djalali, C., Dodge, G. E., Drozdov, V., Dupre, R., Egiyan, H., El Alaoui, A., Elouadrhiri, L., Eugenio, P., Fedotov, G., Filippi, A., Ghandilyan, Y., Gilfoyle, G. P., Golovatch, E., Gothe, R. W., Griffioen, K. A., Guidal, M., Guler, N., Guo, L., Hafidi, K., Hakobyan, H., Hanretty, C., Harrison, N., Hattawy, M., Heddle, D., Hicks, K., Holtrop, M., Hyde, C. E., Ilieva, Y., Ireland, D. G., Isupov, E. L., Jenkins, D., Jo, H. S., Johnston, S. C., Joo, K., Joosten, S., Kabir, M. L., Keith, C. D., Keller, D., Khachatryan, G., Khachatryan, M., Khandaker, M., Kim, W., Klein, A., Klein, F. J., Konczykowski, P., Kovacs, K., Kubarovsky, V., Lanza, L., Lenisa, P., Livingston, K., Long, E., MacGregor, I. J. D., Markov, N., Mayer, M., McKinnon, B., Meekins, D. G., Meyer, C. A., Mineeva, T., Mirazita, M., Mokeev, V., Movsisyan, A., Camacho, C. Munoz, Nadel-Turonski, P., Niculescu, G., Niccolai, S., Osipenko, M., Ostrovidov, A. I., Paolone, M., Pappalardo, L., Paremuzyan, R., Park, K., Pasyuk, E., Payette, D., Phelps, W., Phillips, S. K., Pierce, J., Pogorelko, O., Poudel, J., Price, J. W., Prok, Y., Protopopescu, D., Raue, B. A., Rizzo, A., Rosner, G., Rossi, P., Sabatie, F., Salgado, C., Schumacher, R. A., Sharabian, Y. G., Shigeyuki, T., Simonyan, A., Skorodumina, Iu, Smith, G. D., Sparveris, N., Sokhan, D., Stepanyan, S., Strakovsky, I. I., Strauch, S., Sulkosky, V., Taiuti, M., Tan, J. A., Ungaro, M., Voutier, E., Wei, X., Weinstein, L. B., Zhang, J., Zhao, Z. W.
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Abstract/Description
We measured the g(1) spin structure function of the deuteron at low Q(2), where QCD can be approximated with chiral perturbation theory (chi PT). The data cover the resonance region, up to an invariant mass of W approximate to 1.9 GeV. The generalized Gerasimov-Drell-Hearn sum, the moment Gamma(d)(1) and the spin polarizability gamma(d)(0) are precisely determined down to a minimum Q(2) of 0.02 GeV2 for the first time, about 2.5 times lower than that of previous data. We compare them to...
Show moreWe measured the g(1) spin structure function of the deuteron at low Q(2), where QCD can be approximated with chiral perturbation theory (chi PT). The data cover the resonance region, up to an invariant mass of W approximate to 1.9 GeV. The generalized Gerasimov-Drell-Hearn sum, the moment Gamma(d)(1) and the spin polarizability gamma(d)(0) are precisely determined down to a minimum Q(2) of 0.02 GeV2 for the first time, about 2.5 times lower than that of previous data. We compare them to several chi PT calculations and models. These results are the first in a program of benchmark measurements of polarization observables in the chi PT domain.
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Date Issued
2018-02-08
Identifier
FSU_libsubv1_wos_000424507800011, 10.1103/PhysRevLett.120.062501
Format
Citation
Interaction-Driven Spontaneous Quantum Hall Effect on a Kagome Lattice
Title
Interaction-driven Spontaneous Quantum Hall Effect On A Kagome Lattice.
Creator
Zhu, W., Gong, Shou-Shu, Zeng, Tian-Sheng, Fu, Liang, Sheng, D. N.
Abstract/Description
Topological states of matter have been widely studied as being driven by an external magnetic field, intrinsic spin-orbital coupling, or magnetic doping. Here, we unveil an interaction-driven spontaneous quantum Hall effect (a Chern insulator) emerging in an extended fermion-Hubbard model on a kagome lattice, based on a state-of-the-art density-matrix renormalization group on cylinder geometry and an exact diagonalization in torus geometry. We first demonstrate that the proposed model...
Show moreTopological states of matter have been widely studied as being driven by an external magnetic field, intrinsic spin-orbital coupling, or magnetic doping. Here, we unveil an interaction-driven spontaneous quantum Hall effect (a Chern insulator) emerging in an extended fermion-Hubbard model on a kagome lattice, based on a state-of-the-art density-matrix renormalization group on cylinder geometry and an exact diagonalization in torus geometry. We first demonstrate that the proposed model exhibits an incompressible liquid phase with doublet degenerate ground states as time-reversal partners. The explicit spontaneous time-reversal symmetry breaking is determined by emergent uniform circulating loop currents between nearest neighbors. Importantly, the fingerprint topological nature of the ground state is characterized by quantized Hall conductance. Thus, we identify the liquid phase as a quantum Hall phase, which provides a "proof-of-principle" demonstration of the interaction-driven topological phase in a topologically trivial noninteracting band.
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Date Issued
2016-08-23
Identifier
FSU_libsubv1_wos_000382007600009, 10.1103/PhysRevLett.117.096402
Format
Citation
Anomalous Thermal Conductivity And Magnetic Torque Response In The Honeycomb Magnet Alpha-rucl3
Title
Anomalous Thermal Conductivity And Magnetic Torque Response In The Honeycomb Magnet Alpha-rucl3.
Creator
Leahy, Ian A., Pocs, Christopher A., Siegfried, Peter E., Graf, David, Do, S.-H., Choi, Kwang-Yong, Normand, B., Lee, Minhyea
Abstract/Description
We report on the unusual behavior of the in-plane thermal conductivity. and torque tau response in the Kitaev-Heisenberg material alpha-RuCl3. kappa shows a striking enhancement with linear growth beyond H = 7 T, where magnetic order disappears, while t for both of the in-plane symmetry directions shows an anomaly at the same field. The temperature and field dependence of kappa are far more complex than conventional phonon and magnon contributions, and require us to invoke the presence of...
Show moreWe report on the unusual behavior of the in-plane thermal conductivity. and torque tau response in the Kitaev-Heisenberg material alpha-RuCl3. kappa shows a striking enhancement with linear growth beyond H = 7 T, where magnetic order disappears, while t for both of the in-plane symmetry directions shows an anomaly at the same field. The temperature and field dependence of kappa are far more complex than conventional phonon and magnon contributions, and require us to invoke the presence of unconventional spin excitations whose properties are characteristic of a field-induced spin-liquid phase related to the enigmatic physics of the Kitaev model in an applied magnetic field.
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Date Issued
2017-05-05
Identifier
FSU_libsubv1_wos_000400673100007, 10.1103/PhysRevLett.118.187203
Format
Citation
Direct Evidence of Octupole Deformation in Neutron-Rich Ba-144
Title
Direct Evidence of Octupole Deformation in Neutron-Rich Ba-144.
Creator
Bucher, B., Zhu, S., Wu, C. Y., Janssens, R. V. F., Cline, D., Hayes, A. B., Albers, M., Ayangeakaa, A. D., Butler, P. A., Campbell, C. M., Carpenter, M. P., Chiara, C. J.,...
Show moreBucher, B., Zhu, S., Wu, C. Y., Janssens, R. V. F., Cline, D., Hayes, A. B., Albers, M., Ayangeakaa, A. D., Butler, P. A., Campbell, C. M., Carpenter, M. P., Chiara, C. J., Clark, J. A., Crawford, H. L., Cromaz, M., David, H. M., Dickerson, C., Gregor, E. T., Harker, J., Hoffman, C. R., Kay, B. P., Kondev, F. G., Korichi, A., Lauritsen, T., Macchiavelli, A. O., Pardo, R. C., Richard, A., Riley, M. A., Savard, G., Scheck, M., Seweryniak, D., Smith, M. K., Vondrasek, R., Wiens, A.
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Abstract/Description
The neutron-rich nucleus Ba-144 (t(1/2) = 11.5 s) is expected to exhibit some of the strongest octupole correlations among nuclei with mass numbers A less than 200. Until now, indirect evidence for such strong correlations has been inferred from observations such as enhanced E1 transitions and interleaving positive- and negative-parity levels in the ground-state band. In this experiment, the octupole strength was measured directly by sub-barrier, multistep Coulomb excitation of a post...
Show moreThe neutron-rich nucleus Ba-144 (t(1/2) = 11.5 s) is expected to exhibit some of the strongest octupole correlations among nuclei with mass numbers A less than 200. Until now, indirect evidence for such strong correlations has been inferred from observations such as enhanced E1 transitions and interleaving positive- and negative-parity levels in the ground-state band. In this experiment, the octupole strength was measured directly by sub-barrier, multistep Coulomb excitation of a post-accelerated 650-MeV Ba-144 beam on a 1.0-mg/cm(2) Pb-208 target. The measured value of the matrix element, < 3(1)(-)parallel to M(E3)parallel to 0(1)(+)> = 0.65((+17)(-23)) eb(3/2,) corresponds to a reduced Bd(E3) transition probability of 48((+25)(-34)) W.u. This result represents an unambiguous determination of the octupole collectivity, is larger than any available theoretical prediction, and is consistent with octupole deformation.
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Date Issued
2016-03-17
Identifier
FSU_libsubv1_wos_000372432700004, 10.1103/PhysRevLett.116.112503
Format
Citation
Electromagnetic Moments Of Radioactive Te-136 And The Emergence Of Collectivity 2p Circle Plus 2n Outside Of Double-magic Sn-132
Title
Electromagnetic Moments Of Radioactive Te-136 And The Emergence Of Collectivity 2p Circle Plus 2n Outside Of Double-magic Sn-132.
Creator
Allmond, J. M., Stuchbery, A. E., Baktash, C., Gargano, A., Galindo-Uribarri, A., Radford, D. C., Bingham, C. R., Brown, B. A., Coraggio, L., Covello, A., Danchev, M., Gross, C....
Show moreAllmond, J. M., Stuchbery, A. E., Baktash, C., Gargano, A., Galindo-Uribarri, A., Radford, D. C., Bingham, C. R., Brown, B. A., Coraggio, L., Covello, A., Danchev, M., Gross, C. J., Hausladen, P. A., Itaco, N., Lagergren, K., Padilla-Rodal, E., Pavan, J., Riley, M. A., Stone, N. J., Stracener, D. W., Varner, R. L., Yu, C.-H.
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Abstract/Description
Radioactive Te-136 has two valence protons and two valence neutrons outside of the Sn-132 double shell closure, providing a simple laboratory for exploring the emergence of collectivity and nucleon-nucleon interactions. Coulomb excitation of Te-136 on a titanium target was utilized to determine an extensive set of electromagnetic moments for the three lowest-lying states, including B(E2; 01(+) -> 2(1)(+)), Q(2(1)(+)), and g(2(1)(+)). The results indicate that the first-excited state, 2(1)(+),...
Show moreRadioactive Te-136 has two valence protons and two valence neutrons outside of the Sn-132 double shell closure, providing a simple laboratory for exploring the emergence of collectivity and nucleon-nucleon interactions. Coulomb excitation of Te-136 on a titanium target was utilized to determine an extensive set of electromagnetic moments for the three lowest-lying states, including B(E2; 01(+) -> 2(1)(+)), Q(2(1)(+)), and g(2(1)(+)). The results indicate that the first-excited state, 2(1)(+), composed of the simple 2p circle plus 2n system, is prolate deformed, and its wave function is dominated by excited valence neutron configurations, but not to the extent previously suggested. It is demonstrated that extreme sensitivity of g(2(1)(+))to the proton and neutron contributions to the wave function provides unique insight into the nature of emerging collectivity, and g(2(1)(+)) was used to differentiate among several state-of-the-art theoretical calculations. Our results are best described by the most recent shell model calculations.
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Date Issued
2017-03-03
Identifier
FSU_libsubv1_wos_000396045900006, 10.1103/PhysRevLett.118.092503
Format
Citation
Energy Gaps and Layer Polarization of Integer and Fractional Quantum Hall States in Bilayer Graphene
Title
Energy Gaps and Layer Polarization of Integer and Fractional Quantum Hall States in Bilayer Graphene.
Creator
Shi, Yanmeng, Lee, Yongjin, Che, Shi, Pi, Ziqi, Espiritu, Timothy, Stepanov, Petr, Smirnov, Dmitry, Lau, Chun Ning, Zhang, Fan
Abstract/Description
Owing to the spin, valley, and orbital symmetries, the lowest Landau level in bilayer graphene exhibits multicomponent quantum Hall ferromagnetism. Using transport spectroscopy, we investigate the energy gaps of integer and fractional quantum Hall (QH) states in bilayer graphene with controlled layer polarization. The state at filling factor nu = 1 has two distinct phases: a layer polarized state that has a larger energy gap and is stabilized by high electric field, and a hitherto unobserved...
Show moreOwing to the spin, valley, and orbital symmetries, the lowest Landau level in bilayer graphene exhibits multicomponent quantum Hall ferromagnetism. Using transport spectroscopy, we investigate the energy gaps of integer and fractional quantum Hall (QH) states in bilayer graphene with controlled layer polarization. The state at filling factor nu = 1 has two distinct phases: a layer polarized state that has a larger energy gap and is stabilized by high electric field, and a hitherto unobserved interlayer coherent state with a smaller gap that is stabilized by large magnetic field. In contrast, the nu = 2/3 quantum Hall state and a feature at nu = 1/2 are only resolved at finite electric field and large magnetic field. These results underscore the importance of controlling layer polarization in understanding the competing symmetries in the unusual QH system of BLG.
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Date Issued
2016-02-05
Identifier
FSU_libsubv1_wos_000369495000015, 10.1103/PhysRevLett.116.056601
Format
Citation
Probing The Single-particle Character Of Rotational States In F-19 Using A Short-lived Isomeric Beam
Title
Probing The Single-particle Character Of Rotational States In F-19 Using A Short-lived Isomeric Beam.
Creator
Santiago-Gonzalez, D., Auranen, K., Avila, M. L., Ayangeakaa, A. D., Back, B. B., Bottoni, S., Carpenter, M. P., Chen, J., Deibel, C. M., Hood, A. A., Hoffman, C. R., Janssens,...
Show moreSantiago-Gonzalez, D., Auranen, K., Avila, M. L., Ayangeakaa, A. D., Back, B. B., Bottoni, S., Carpenter, M. P., Chen, J., Deibel, C. M., Hood, A. A., Hoffman, C. R., Janssens, R. V. F., Jiang, C. L., Kay, B. P., Kuvin, S. A., Lauer, A., Schiffer, J. P., Sethi, J., Talwar, R., Wiedenhover, I., Winkelbauer, J., Zhu, S.
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Abstract/Description
A beam containing a substantial component of both the J(pi) = 5(+), T-1/2 = 162 ns isomeric state of F-18 and its 1(+), 109.77-min ground state is utilized to study members of the ground-state rotational band in F-19 through the neutron transfer reaction (d,p) in inverse kinematics. The resulting spectroscopic strengths confirm the single-particle nature of the 13/2(+) band-terminating state. The agreement between shell-model calculations using an interaction constructed within the sd shell,...
Show moreA beam containing a substantial component of both the J(pi) = 5(+), T-1/2 = 162 ns isomeric state of F-18 and its 1(+), 109.77-min ground state is utilized to study members of the ground-state rotational band in F-19 through the neutron transfer reaction (d,p) in inverse kinematics. The resulting spectroscopic strengths confirm the single-particle nature of the 13/2(+) band-terminating state. The agreement between shell-model calculations using an interaction constructed within the sd shell, and our experimental results reinforces the idea of a single-particle-collective duality in the descriptions of the structure of atomic nuclei.
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Date Issued
2018-03-23
Identifier
FSU_libsubv1_wos_000428167200009, 10.1103/PhysRevLett.120.122503
Format
Citation
Slave Boson Theory Of Orbital Differentiation With Crystal Field Effects
Title
Slave Boson Theory Of Orbital Differentiation With Crystal Field Effects: Application To Uo2.
Creator
Lanata, Nicola, Yao, Yongxin, Deng, Xiaoyu, Dobrosavljevic, Vladimir, Kotliar, Gabriel
Abstract/Description
We derive an exact operatorial reformulation of the rotational invariant slave boson method, and we apply it to describe the orbital differentiation in strongly correlated electron systems starting from first principles. The approach enables us to treat strong electron correlations, spin-orbit coupling, and crystal field splittings on the same footing by exploiting the gauge invariance of the mean-field equations. We apply our theory to the archetypical nuclear fuel UO2 and show that the...
Show moreWe derive an exact operatorial reformulation of the rotational invariant slave boson method, and we apply it to describe the orbital differentiation in strongly correlated electron systems starting from first principles. The approach enables us to treat strong electron correlations, spin-orbit coupling, and crystal field splittings on the same footing by exploiting the gauge invariance of the mean-field equations. We apply our theory to the archetypical nuclear fuel UO2 and show that the ground state of this system displays a pronounced orbital differentiation within the 5f manifold, with Mott-localized Gamma(8) and extended Gamma(7) electrons.
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Date Issued
2017-03-23
Identifier
FSU_libsubv1_wos_000397804300012, 10.1103/PhysRevLett.118.126401
Format
Citation
Static and Dynamical Properties of the Spin-1/2 Equilateral Triangular-Lattice Antiferromagnet Ba3CoSb2O9
Title
Static and Dynamical Properties of the Spin-1/2 Equilateral Triangular-Lattice Antiferromagnet Ba3CoSb2O9.
Creator
Ma, J., Kamiya, Y., Hong, Tao, Cao, H. B., Ehlers, G., Tian, W., Batista, C. D., Dun, Z. L., Zhou, H. D., Matsuda, M.
Abstract/Description
We present single-crystal neutron scattering measurements of the spin-1/2 equilateral triangular-lattice antiferromagnet Ba3CoSb2O9. Besides confirming that the Co2+ magnetic moments lie in the ab plane for zero magnetic field and then determining all the exchange parameters of the minimal quasi-2D spin Hamiltonian, we provide conclusive experimental evidence of magnon decay through observation of intrinsic line broadening. Through detailed comparisons with the linear and nonlinear spin-wave...
Show moreWe present single-crystal neutron scattering measurements of the spin-1/2 equilateral triangular-lattice antiferromagnet Ba3CoSb2O9. Besides confirming that the Co2+ magnetic moments lie in the ab plane for zero magnetic field and then determining all the exchange parameters of the minimal quasi-2D spin Hamiltonian, we provide conclusive experimental evidence of magnon decay through observation of intrinsic line broadening. Through detailed comparisons with the linear and nonlinear spin-wave theories, we also point out that the large-S approximation, which is conventionally employed to predict magnon decay in noncollinear magnets, is inadequate to explain our experimental observation. Thus, our results call for a new theoretical framework for describing excitation spectra in low-dimensional frustrated magnets under strong quantum effects.
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Date Issued
2016-02-24
Identifier
FSU_libsubv1_wos_000370816600004, 10.1103/PhysRevLett.116.087201
Format
Citation
Thermodynamic Measurement of Angular Anisotropy at the Hidden Order Transition of URu2Si2
Title
Thermodynamic Measurement Of Angular Anisotropy At The Hidden Order Transition Of Uru2si2.
Creator
Trinh, Jennifer, Bruck, Ekkes, Siegrist, Theo, Flint, Rebecca, Chandra, Premala, Coleman, Piers, Ramirez, Arthur P.
Abstract/Description
The heavy fermion compound URu2Si2 continues to attract great interest due to the unidentified hidden order it develops below 17.5 K. The unique Ising character of the spin fluctuations and low-temperature quasiparticles is well established. We present detailed measurements of the angular anisotropy of the nonlinear magnetization that reveal a cos(4)theta Ising anisotropy both at and above the ordering transition. With Landau theory, we show this implies a strongly Ising character of the...
Show moreThe heavy fermion compound URu2Si2 continues to attract great interest due to the unidentified hidden order it develops below 17.5 K. The unique Ising character of the spin fluctuations and low-temperature quasiparticles is well established. We present detailed measurements of the angular anisotropy of the nonlinear magnetization that reveal a cos(4)theta Ising anisotropy both at and above the ordering transition. With Landau theory, we show this implies a strongly Ising character of the itinerant hidden order parameter.
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Date Issued
2016-10-05
Identifier
FSU_libsubv1_wos_000385341600008, 10.1103/PhysRevLett.117.157201
Format
Citation
Tunable Symmetries of Integer and Fractional Quantum Hall Phases in Heterostructures with Multiple Dirac Bands
Title
Tunable Symmetries of Integer and Fractional Quantum Hall Phases in Heterostructures with Multiple Dirac Bands.
Creator
Stepanov, Petr, Barlas, Yafis, Espiritu, Tim, Che, Shi, Watanabe, Kenji, Taniguchi, Takashi, Smirnov, Dmitry, Lau, Chun Ning
Abstract/Description
The copresence of multiple Dirac bands in few-layer graphene leads to a rich phase diagram in the quantum Hall regime. Using transport measurements, we map the phase diagram of BN-encapsulated ABA-stacked trilayer graphene as a function charge density n, magnetic field B, and interlayer displacement field D, and observe transitions among states with different spin, valley, orbital, and parity polarizations. Such a rich pattern arises from crossings between Landau levels from different...
Show moreThe copresence of multiple Dirac bands in few-layer graphene leads to a rich phase diagram in the quantum Hall regime. Using transport measurements, we map the phase diagram of BN-encapsulated ABA-stacked trilayer graphene as a function charge density n, magnetic field B, and interlayer displacement field D, and observe transitions among states with different spin, valley, orbital, and parity polarizations. Such a rich pattern arises from crossings between Landau levels from different subbands, which reflect the evolving symmetries that are tunable in situ. At D = 0, we observe fractional quantum Hall (FQH) states at filling factors 2/3 and -11/3. Unlike those in bilayer graphene, these FQH states are destabilized by a small interlayer potential that hybridizes the different Dirac bands.
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Date Issued
2016-08-12
Identifier
FSU_libsubv1_wos_000381478800009, 10.1103/PhysRevLett.117.076807
Format
Citation