TY - JOUR

T1 - Dependences of the Transport Scattering Time and Quantum Lifetime on the Two-Dimensional Electron Gas Density in Modulation-Doped Single GaAs Quantum Wells with AlAs/GaAs Short-Period Superlattice Barriers

AU - Bykov, A. A.

AU - Strygin, I. S.

AU - Goran, A. V.

AU - Nomokonov, D. V.

AU - Bakarov, A. K.

N1 - Funding Information: This work was supported by the Russian Foundation for Basic Research (project nos. 18-02-00603 and 20-02-00309). Publisher Copyright: © 2020, Pleiades Publishing, Inc. Copyright: Copyright 2020 Elsevier B.V., All rights reserved.

PY - 2020/10

Y1 - 2020/10

N2 - The dependences of the transport scattering time τt, quantum lifetime τq, and their ratio τt/τq on the density ne of the electron gas in modulation-doped single GaAs quantum wells with AlAs/GaAs short-period super-lattice barriers are investigated. The experimental dependences are explained in terms of electron scattering by remote ionized donors with an effective two-dimensional concentration nR* and background impurities with a three-dimensional concentration nB. An expression for nR*(ne) is obtained including the contribution of X-valley electrons localized in AlAs layers to the suppression of scattering by the random potential of remote donors. It is shown that the experimentally observed abrupt increase in τt and τq with an increase in ne above a certain critical value nec is related to a decrease in nR*. It is established that the drop in τt/τq observed for electron densities ne > nec occurs because scattering by the random potential of background impurities in this two-dimensional system with a decrease in nR* limits an increase in τt more considerably than an increase in τq.

AB - The dependences of the transport scattering time τt, quantum lifetime τq, and their ratio τt/τq on the density ne of the electron gas in modulation-doped single GaAs quantum wells with AlAs/GaAs short-period super-lattice barriers are investigated. The experimental dependences are explained in terms of electron scattering by remote ionized donors with an effective two-dimensional concentration nR* and background impurities with a three-dimensional concentration nB. An expression for nR*(ne) is obtained including the contribution of X-valley electrons localized in AlAs layers to the suppression of scattering by the random potential of remote donors. It is shown that the experimentally observed abrupt increase in τt and τq with an increase in ne above a certain critical value nec is related to a decrease in nR*. It is established that the drop in τt/τq observed for electron densities ne > nec occurs because scattering by the random potential of background impurities in this two-dimensional system with a decrease in nR* limits an increase in τt more considerably than an increase in τq.

KW - PARTICLE RELAXATION-TIME

KW - DC CONDUCTIVITIES

KW - OSCILLATIONS

KW - RESISTANCE

KW - SYSTEM

KW - AC

UR - http://www.scopus.com/inward/record.url?scp=85097622049&partnerID=8YFLogxK

U2 - 10.1134/S0021364020190054

DO - 10.1134/S0021364020190054

M3 - Article

AN - SCOPUS:85097622049

VL - 112

SP - 437

EP - 443

JO - JETP Letters

JF - JETP Letters

SN - 0021-3640

IS - 7

ER -