The role of background impurities in the single particle relaxation lifetime of a two-dimensional electron gas

Abstract

We re-examine the quantum tau_q and transport tau_t scattering lifetimes due to background impurities in two-dimensional systems. We show that the well-known logarithmic divergence in the quantum lifetime is due to the non-physical assumption of an infinitely thick heterostructure, and demonstrate that the existing non-divergent multiple scattering theory can lead to unphysical quantum scattering lifetimes in high quality heterostructures. We derive a non-divergent scattering lifetime for finite thickness structures, which can be used both with lowest order perturbation theory and the multiple scattering theory. We calculate the quantum and transport lifetimes for electrons in generic GaAs-AlGaAs heterostructures, and find that the correct `rule of thumb' to distinguish the dominant scattering mechanisms in GaAs heterostructures should be tau_t/tau_q < 10 for background impurities and tau_t/tau_q > 10 for remote impurities. Finally we present the first comparison of theoretical results for tau_q and tau_t with experimental data from a GaAs 2DEG in which only background impurity scattering is present. We obtain excellent agreement between the calculations and experimental data, and are able to extract the background impurity density in both the GaAs and AlGaAs regions.

Revtex4, 8 pages, 6 figures

References in corpus (5)

• Topologically-Protected Qubits from a Possible Non-Abelian Fractional Quantum Hall State
• Evidence for an Anisotropic State of Two-Dimensional Electrons in High Landau Levels
• Spin Susceptibility of an Ultra-Low Density Two Dimensional Electron System
• Limit to 2D mobility in modulation-doped GaAs quantum structures: How to achieve a mobility of 100 millions
• Zero-Resistance States Induced by Electromagnetic-Wave Excitation in GaAs/AlGaAs Heterostructures

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