Scattering Mechanisms in a High Mobility Low Density Carbon-Doped (100) GaAs Two-Dimensional Hole System

Abstract

We report on a systematic study of the density dependence of mobility in a low-density Carbon-doped (100) GaAs two-dimensional hole system (2DHS). At T= 50 mK, a mobility of 2.6 x 10^6 cm^2/Vs at a density p=6.2 x 10^10 cm^- was measured. This is the highest mobility reported for a 2DHS to date. Using a back-gated sample geometry, the density dependence of mobility was studied from 2.8 x 10^10 cm^-2 to 1 x 10^11 cm^-2. The mobility vs. density cannot be fit to a power law dependence of the form mu ~ p^alpha using a single exponent alpha. Our data indicate a continuous evolution of the power law with alpha ranging from ~ 0.7 at high density and increasing to ~ 1.7 at the lowest densities measured. Calculations specific to our structure indicate a crossover of the dominant scattering mechanism from uniform background impurity scattering at high density to remote ionized impurity scattering at low densities. This is the first observation of a carrier density-induced transition from background impurity dominated to remote dopant dominated transport in a single sample.

4 pages, 5 figures, prepared with LaTex2e

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• Exploration of the Limits to Mobility in Two-Dimensional Hole Systems in GaAs/AlGaAs Quantum Wells
• Weak quantization of non-interacting topological Anderson insulator
• Josephson-like tunnel resonance and large Coulomb drag in GaAs-based electron-hole bilayers
• Signatures of quantum mechanical Zeeman effect in classical transport due to topological properties of two-dimensional spin-3/2 holes
• Ultraclean two-dimensional hole systems with mobilities exceeding 10${}^7$ cm${}^2$/Vs
• Thermal melting of a quantum electron solid in the presence of strong disorder: Anderson versus Wigner