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Title

Quantum Limit Transport And Destruction Of The Weyl Nodes In Taas.

Creator

Ramshaw, B. J., Modic, K. A., Shekhter, Arkady, Zhang, Yi, Kim, EunAh, Moll, Philip J. W., Bachmann, Maja D., Chan, M. K., Betts, J. B., Balakirev, F., Migliori, A., Ghimire, N...
Show moreRamshaw, B. J., Modic, K. A., Shekhter, Arkady, Zhang, Yi, Kim, EunAh, Moll, Philip J. W., Bachmann, Maja D., Chan, M. K., Betts, J. B., Balakirev, F., Migliori, A., Ghimire, N. J., Bauer, E. D., Ronning, F., McDonald, R. D.
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Abstract/Description

Weyl fermions are a recently discovered ingredient for correlated states of electronic matter. A key difficulty has been that real materials also contain nonWeyl quasiparticles, and disentangling the experimental signatures has proven challenging. Here we use magnetic fields up to 95 T to drive the Weyl semimetal TaAs far into its quantum limit, where only the purely chiral 0th Landau levels of the Weyl fermions are occupied. We find the electrical resistivity to be nearly independent of...
Show moreWeyl fermions are a recently discovered ingredient for correlated states of electronic matter. A key difficulty has been that real materials also contain nonWeyl quasiparticles, and disentangling the experimental signatures has proven challenging. Here we use magnetic fields up to 95 T to drive the Weyl semimetal TaAs far into its quantum limit, where only the purely chiral 0th Landau levels of the Weyl fermions are occupied. We find the electrical resistivity to be nearly independent of magnetic field up to 50 T: unusual for conventional metals but consistent with the chiral anomaly for Weyl fermions. Above 50 T we observe a twoorderofmagnitude increase in resistivity, indicating that a gap opens in the chiral Landau levels. Above 80 T we observe strong ultrasonic attenuation below 2 K, suggesting a mesoscopically textured state of matter. These results point the way to inducing new correlated states of matter in the quantum limit of Weyl semimetals.
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Date Issued

20180607

Identifier

FSU_libsubv1_wos_000434379800014, 10.1038/s41467018045429

Format

Citation


Title

Resonant Torsion Magnetometry In Anisotropic Quantum Materials.

Creator

Modic, K. A., Bachmann, Maja D., Ramshaw, B. J., Arnold, F., Shirer, K. R., Estry, Amelia, Betts, J. B., Ghimire, Nirmal J., Bauer, E. D., Schmidt, Marcus, Baenitz, Michael,...
Show moreModic, K. A., Bachmann, Maja D., Ramshaw, B. J., Arnold, F., Shirer, K. R., Estry, Amelia, Betts, J. B., Ghimire, Nirmal J., Bauer, E. D., Schmidt, Marcus, Baenitz, Michael, Svanidze, E., McDonald, Ross D., Shekhter, Arkady, Moll, Philip J. W.
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Abstract/Description

Unusual behavior in quantum materials commonly arises from their effective lowdimensional physics, reflecting the underlying anisotropy in the spin and charge degrees of freedom. Here we introduce the magnetotropic coefficient k = partial derivative F2/partial derivative theta(2), the second derivative of the free energy F with respect to the magnetic field orientation theta in the crystal. We show that the magnetotropic coefficient can be quantitatively determined from a shift in the...
Show moreUnusual behavior in quantum materials commonly arises from their effective lowdimensional physics, reflecting the underlying anisotropy in the spin and charge degrees of freedom. Here we introduce the magnetotropic coefficient k = partial derivative F2/partial derivative theta(2), the second derivative of the free energy F with respect to the magnetic field orientation theta in the crystal. We show that the magnetotropic coefficient can be quantitatively determined from a shift in the resonant frequency of a commercially available atomic force microscopy cantilever under magnetic field. This detection method enables part per 100 million sensitivity and the ability to measure magnetic anisotropy in nanogramscale samples, as demonstrated on the Weyl semimetal NbP. Measurement of the magnetotropic coefficient in the spinliquid candidate RuCl3 highlights its sensitivity to anisotropic phase transitions and allows a quantitative comparison to other thermodynamic coefficients via the Ehrenfest relations.
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Date Issued

20180928

Identifier

FSU_libsubv1_wos_000445886000001, 10.1038/s4146701806412w

Format

Citation