Conductance fluctuations in PbTe wide parabolic quantum wells

Oswald, Josef; Heigl, G.; Span, G.; Homer, A.; Ganitzer, P.; Maude, D. K.; Portal, J. C.

doi:10.1016/0921-4526(96)00442-5

Cited by 6 publications

(10 citation statements)

References 18 publications

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“…We interpret this behavior in terms of phasecoherent electrontransport, which takes advantage of a dramatic enhancement of the phasecoherence length of electrons in edgechannels and edge channel loops in the bulk region. details can be obtained from [2,4,5,6]. The left part of Fig.…”

Section: Resultsmentioning

confidence: 99%

“…The experiments are performed with a standard lock-in technique like described in [2,4,5,6] Figure 1 shows R xx , R xy and non-local data. In addition, the R xx data are shown after subtracting the linear back ground (∆R xx ).…”

Section: Resultsmentioning

confidence: 99%

“…WPQWs can be made much more easily using the n-i-p-i concept with Lead Telluride (PbTe) and have been recently successfully realized and investigated [2,3]. The main facts are as follows: The quantum Hall effect is suppressed and replaced by conductance fluctuations (CF) of universal amplitude e 2 /h [4,5,6]. The magnetotransport is dominated by edge channel conduction with permanent back scattering, which gives rise to a linear increase of R xx with magnetic field [7].…”

Section: Introductionmentioning

confidence: 99%

“…The quantum Hall effect is suppressed and replaced by conductance fluctuations (CF) of universal amplitude e 2 /h [4,5,6]. The magnetotransport is dominated by edge channel conduction with strong, permanent back scattering, which gives rise to an overall linear increase of R xx with magnetic field [7]:…”

Section: Introductionmentioning

confidence: 99%

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Magnetotransport in wide parabolic PbTe quantum wells

et al. 1996

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The 3D-and 2D-behaviour of wide parabolic PbTe single quantum wells, which consist of PbTe p-n-p-structures, are studied theoretically and experimentally. A simple model combines the 2D-subband levels and the 3D-Landau levels in order to calculate the density of states in a magnetic field perpendicular to the 2D plane. It is shown that at a channel width of about 300nm on can expect to observe 3D-and 2D-behaviour at the same time. Magnetotransport experiments in selectively contacted Hall bar samples are performed at temperatures down to T = 50 mK and at magnetic fields up to B = 17 T.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Magnetotransport in wide parabolic PbTe quantum wells

et al. 1996

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“…The wide parabolic quantum wells at large filling factors had been created by the Narrow Gap Semiconductor PbTe and instead of quantum Hall plateaus magneto-resistance fluctuations have been found at temperatures below 100 mK and at small current of the order of a few nA. The temperature and current dependence of these fluctuations that also appeared in a so-called non-local contact configuration even at macroscopic sample size [30] indicated the involvement of quantum channels [31]. In this context, the relations between the potentials of channels that meet at non-equilibrium situation seem to be valid also for that regime far from the standard quantum Hall regime in the clean two-dimensional case.…”

Section: Discussionmentioning

confidence: 99%

Linking Non-equilibrium Transport with the Many Particle Fermi Sea in the Quantum Hall Regime

Oswald¹

2016

Research Advances in Quantum Dynamics

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Tνe communξcatξon of tνe electron system wξtν tνe outsξde world at low excξtatξon transport experξments νappens by excνangξng electrons at tνe Fermξ level. We argue tνat tνe locatξons wνere tνξs ξs possξble ξn tνe quantum Hall effect regξme are tνe so-called edge cνannels. We explaξn tνat tνese cνannels can be understood as a more general representatξon of tνe many-partξcle quantum Hall QH system close to equξlξbrξum tνat allows descrξbξng transport due to non-equξlξbrξum on a very fundamental level. "ased on fundamental prξncξples of quantum pνysξcs, a transfer matrξx formulatξon for tνe local non-equξlξbrξum electrocνemξcal potentξal ξn a network of ξnterconnected dξrected quantum cνannels can be used to solve tνe lateral dξstrξbutξon of tνe non-equξlξbrξum excξtatξon potentξals. Instead of usξng tνe Landauer formula or otνer tools lξke tνe Kubo formula for addressξng conductance's just a transfer matrξx formulatξon for tνe transfer of electrocνemξcal potentξals ξs used to fξnd tνe self-consξstent lateral dξstrξbutξon of tνe non-equξlξbrξum electrocνemξcal potentξals. Currents and potentξals tνat are measured at contacts are only calculated as a post-processξng step rξgνt at tνe contacts, and tνey allow calculatξng all tνe resξstances and conductance's lξke known from QH experξ-ments. Tνe ξnterplay between transport and tνe many-partξcle system ξs of general ξnterest wνen dealξng wξtν accessξng ξnformatξon about quantum systems. Our approacν allows modelξng electron systems ξn tνe QH regξme for realξstξc sample geometrξes, ξncludξng ξnνomogeneξtξes, lξke present ξn real samples or tνat are forced by gate electrodes as well as tνe random dξsorder potentξal. We combξne our network model for transport wξtν tνe Hartree Fock metνod tνat allows tνe ξnclusξon of realξstξc screenξng effects as well as tνe magnetξc fξeld-dependent enνanced g-factor.Keywords: network model, quantum Hall effect, magneto-transport, conductance quantξzatξon, non-equξlξbrξum transport, excνange ξnteractξon, Hartree-Fock approxξ-matξon, many partξcle quantum system © 2016 The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. . IntroductionEven more tνan years after dξscoverξng tνe ξnteger quantum Hall effect [ ], ξt ξs stξll a lξvely dξscussed topξc at many conferences. In tνe quantum Hall QH regξme, tνe many-partξcle quantum nature of tνe electron system can be studξed from mesoscopξc to nearly macroscopξc lengtν scales. Tνe cνallenge ξn modelξng electron transport ξn tνξs regξme ξs tνat tνe manypartξcle quantum states of tνe electron system exξst as statξonary states at tνermal equξlξbrξ-um, wνξle transport ξs drξven by ξntroducξng devξatξons from tνe equξlξbrξum. Even for tνe QH experξments tνat νappen close to tνermal equξlξbrξum, a dξrect modelξng of current flow does not fξt tνe world of statξona...

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Anomalous magnetotransport in wide quantum wells

Oswald

Span

Homer

et al. 1997

Solid State Communications

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We present magneto transport experiments of quasi 3D PbTe wide quantum wells. A plateau-like structure in the Hall resistance is observed, which corresponds to the Shubnikov de Haas oscillations in the same manner as known from the quantum Hall effect. The onsets of plateaux in Rxy do not correspond to 2D filling factors but coincide with the occupation of 3D (bulk-) Landau levels. At the same time a non-local signal is observed which corresponds to the structure in Rxx and Rxy and fulfils exactly the Onsager-Casimir relation (Rij,kl(B) = Rkl,ij(-B)). We explain the behaviour in terms of edge channel transport which is controlled by a permanent backscattering across a system of "percolative EC - loops" in the bulk region. Long range potential fluctuations with an amplitude of the order of the subband splitting are explained to play an essential role in this electron system.Comment: postscript file including 3 figs, 5 page

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Conductance fluctuations in PbTe wide parabolic quantum wells

Abstract: Abstract

Cited by 6 publications

References 18 publications

Magnetotransport in wide parabolic PbTe quantum wells

Magnetotransport in wide parabolic PbTe quantum wells

Linking Non-equilibrium Transport with the Many Particle Fermi Sea in the Quantum Hall Regime

Anomalous magnetotransport in wide quantum wells

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