Diffusion Thermopower of a Two-Dimensional Hole Gas in SiGe in a Quantum Hall Insulating State

Possanzini, C.; Fletcher, R.; Coleridge, P. T.; Feng, Y.; Williams, Robin L.; Maan, J.C.

doi:10.1103/physrevlett.90.176601

Cited by 14 publications

(10 citation statements)

References 25 publications

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“…27 Our calculations are based on a noninteracting-electron picture. This is in contrast to recent experimental studies of diffusion thermopower in strongly correlated systems, e.g., those displaying the fractional quantum Hall effect [28][29][30] or low-concentration samples with unconconventional metallic phases. [31][32][33] A temperature gradient can drive an electric current, or, for open electric contacts, generate an electric-voltage gradient.…”

Section: Introductioncontrasting

confidence: 90%

Mesoscopic diffusion thermopower in two-dimensional electron gases

Rojek

König

2014

Phys. Rev. B

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The diffusion of energy that is locally deposited into two-dimensional electron gases by Joule heating generates transverse voltages across devices with broken symmetry. For mesoscopic structures characterized by device dimensions comparable to the energy diffusion length, the resulting thermopower strongly depends on details of the potential profile defined by electric gates. We discuss these mesoscopic features within a diffusion thermopower model and propose schemes to measure the energy diffusion length and its dependence on gate voltage.

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Section: Introductioncontrasting

confidence: 90%

Mesoscopic diffusion thermopower in two-dimensional electron gases

Rojek

König

2014

Phys. Rev. B

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“…To increase the electron diffusion Nernst signals, the S xy d of v = 1/2 may be measured in Si/SiGe heterostructures. Unlike the piezoelectric GaAs/AlGaAs systems, the phonon drag in the Si/SiGe heterostructures is suppressed significantly below 1 K [47][48][49]. As a result, the S xy d of v = 1/2 could be obtained at higher temperatures with correspondingly larger diffusion Nernst signals.…”

Section: Discussionmentioning

confidence: 99%

Thermopower and Nernst measurements in a half-filled lowest Landau level

Liu

Zhang

et al. 2018

Phys. Rev. B

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Motivated by recent proposal by Potter et al. [Phys. Rev. X 6, 031026 (2016)] concerning possible thermoelectric signatures of Dirac composite fermions, we perform a systematic experimental study of thermoelectric transport of an ultrahigh-mobility GaAs/Al x Ga 1-x As two dimensional electron system at filling factor v = 1/2. We demonstrate that the thermopower S xx and Nernst S xy are symmetric and anti-symmetric with respect to B = 0 T, respectively. The measured properties of thermopower S xx at v = 1/2 are consistent with previous experimental results. The Nernst signals S xy of v = 1/2, which have not been reported previously, are non-zero and show a power law relation with temperature in the phonon-drag dominant region.In the electron-diffusion dominant region, the Nernst signals S xy of v = 1/2 are found to be significantly smaller than the linear temperature dependent values predicted by Potter et al., and decreasing with temperature faster than linear dependence.

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“…This has been exploited in investigating the localization transition in a disordered 2DES [3], where the 2DES goes from a purely metallic state to a highly localized one. Similar TP measurements have been used to explore quantum insulating ground states of a bulk 2D electron gas in high magnetic fields [4]. On the other hand, being a measure of entropy per carrier, the third law of thermodynamics requires TP → 0 at T → 0 in delocalized or metallic systems, although the absolute magnitude of TP depends critically on the energy-dependence of scattering mechanism of the conduction electrons.…”

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confidence: 91%

Highly Enhanced Thermopower in Two-Dimensional Electron Systems at Millikelvin Temperatures

et al. 2009

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We report experimental observation of an unexpectedly large thermopower in mesoscopic two-dimensional (2D) electron systems in GaAs/AlGaAs heterostructures at sub-Kelvin temperatures and zero magnetic field. Unlike conventional nonmagnetic high-mobility 2D systems, the thermopower in our devices increases with decreasing temperature below 0.3 K, reaching values in excess of 100 microV/K, thus exceeding the free electron estimate by more than 2 orders of magnitude. With support from a parallel study of the local density of states, we suggest such a phenomenon to be linked to intrinsic localized states and many-body spin correlations in the system.

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Diffusion Thermopower of a Two-Dimensional Hole Gas in SiGe in a Quantum Hall Insulating State

Cited by 14 publications

References 25 publications

Mesoscopic diffusion thermopower in two-dimensional electron gases

Mesoscopic diffusion thermopower in two-dimensional electron gases

Thermopower and Nernst measurements in a half-filled lowest Landau level

Highly Enhanced Thermopower in Two-Dimensional Electron Systems at Millikelvin Temperatures

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