Current Search: Research Repository (x) » National High Magnetic Field Laboratory (x) » Wang, Leizhi (x)
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Title
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Geometric dependence of transport and universal behavior in three dimensional carbon nanostructures.
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Creator
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Wang, Leizhi, Yin, Ming, Jaroszynski, Jan, Park, Ju-Hyun, Mbamalu, Godwin, Datta, Timir
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Abstract/Description
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Carbon nanostructures with the spherical voids exhibit interesting temperature and magnetic field dependent transport properties. By increasing the void size, the structures are tuned from metallic to insulating; in addition, the magnetoresistance (MR) is enhanced. Our investigation in the magnetic fields (B) up to 18 T at temperatures (T) from 250 mK to 20K shows that at high temperatures (T>2 K), the MR crosses over from quadratic to a non-saturating linear dependence with increasing...
Show moreCarbon nanostructures with the spherical voids exhibit interesting temperature and magnetic field dependent transport properties. By increasing the void size, the structures are tuned from metallic to insulating; in addition, the magnetoresistance (MR) is enhanced. Our investigation in the magnetic fields (B) up to 18 T at temperatures (T) from 250 mK to 20K shows that at high temperatures (T>2 K), the MR crosses over from quadratic to a non-saturating linear dependence with increasing magnetic field. Furthermore, all MR data in this temperature regime collapse onto a single curve as a universal function of B/T, following Kohler's rule. Remarkably, the MR also exhibits orientation insensitivity, i.e., it displays a response independent of the direction on the magnetic field. Published by AIP Publishing.
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Date Issued
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2016-09-19
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Identifier
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FSU_libsubv1_wos_000384558700054, 10.1063/1.4963261
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Format
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Citation
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Title
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Scatterings And Quantum Effects In (al, In)n/gan Heterostructures For High-power And High-frequency Electronics.
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Creator
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Wang, Leizhi, Yin, Ming, Khan, Asif, Muhtadi, Sakib, Asif, Fatima, Choi, Eun Sang, Datta, Timir
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Abstract/Description
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Charge transport in the wide-band-gap (Al, In)N/GaN heterostructures with high carrier density approximately 2 x 10(13) cm(-2) is investigated over a large range of temperature (270 mK
Show moreCharge transport in the wide-band-gap (Al, In)N/GaN heterostructures with high carrier density approximately 2 x 10(13) cm(-2) is investigated over a large range of temperature (270 mK <= T <= 280 K) and magnetic field (0 <= B <= 18 T). We observe the first evidence of weak localization in the two-dimensional electron gas in this system. From the Shubnikov-de Haas (SdH) oscillations a relatively light effective mass of 0.23m(e) is determined. Furthermore, the linear dependence with temperature (T < 20 K) of the inelastic scattering rate (tau(-1)(i) proportional to T) is attributed to the phase breaking by electron-electron scattering. Also in the same temperature range the less-than unit ratio of quantum lifetime to Hall transport time (tau(q)/tau(t) < 1) is taken to signify the dominance of small-angle scattering. Above 20 K, with increasing temperature scattering changes from acoustic phonon to optical phonon scattering, resulting in a rapid decrease in carrier mobility and increase in sheet resistance. Suppression of such scatterings will lead to higher mobility and a way forward to high-power and high-frequency electronics.
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Date Issued
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2018-02-07
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Identifier
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FSU_libsubv1_wos_000424387600003, 10.1103/PhysRevApplied.9.024006
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Format
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Citation
