The role of background impurities in the single particle relaxation lifetime of a two-dimensional electron gas - Condensed Matter > Mesoscale and Nanoscale PhysicsReport as inadecuate




The role of background impurities in the single particle relaxation lifetime of a two-dimensional electron gas - Condensed Matter > Mesoscale and Nanoscale Physics - Download this document for free, or read online. Document in PDF available to download.

Abstract: We re-examine the quantum tau q and transport tau t scattering lifetimes dueto background impurities in two-dimensional systems. We show that thewell-known logarithmic divergence in the quantum lifetime is due to thenon-physical assumption of an infinitely thick heterostructure, and demonstratethat the existing non-divergent multiple scattering theory can lead tounphysical quantum scattering lifetimes in high quality heterostructures. Wederive a non-divergent scattering lifetime for finite thickness structures,which can be used both with lowest order perturbation theory and the multiplescattering theory. We calculate the quantum and transport lifetimes forelectrons in generic GaAs-AlGaAs heterostructures, and find that the correct`rule of thumb- to distinguish the dominant scattering mechanisms in GaAsheterostructures should be tau t-tau q < 10 for background impurities andtau t-tau q > 10 for remote impurities. Finally we present the first comparisonof theoretical results for tau q and tau t with experimental data from a GaAs2DEG in which only background impurity scattering is present. We obtainexcellent agreement between the calculations and experimental data, and areable to extract the background impurity density in both the GaAs and AlGaAsregions.



Author: S. J. MacLeod, K. Chan, T. P. Martin, A. R. Hamilton, A. See, A. P. Micolich, M. Aagesen, P. E. Lindelof

Source: https://arxiv.org/



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