Scattering mechanisms in state-of-the-art GaAs/AlGaAs quantum wells

Motivated by recent breakthroughs in molecular beam epitaxy of GaAs/AlGaAs quantum wells [Y. J. Chung et al., Nat. Mater. 20, 632 (2021)], we examine contributions to mobility and quantum mobility from various scattering mechanisms and their dependencies on the electron density. We find that at lower electron densities, nₑ1×10¹¹4pt0excm^-2, both transport and quantum mobility are limited by unintentional background impurities and follow a power-law dependence, ∝nₑ^α, with α≈0.85. Our predictions for quantum mobility are in reasonable agreement with an estimate obtained from the resistivity at filling factor ν=1/2 in a sample of Y. J. Chung et al. with nₑ=1×10¹¹4pt0excm^-2. Consideration of other scattering mechanisms indicates that interface roughness (remote donors) is likely a limiting factor of transport (quantum) mobility at higher electron densities. Future measurements of quantum mobility should yield information on the distribution of background impurities in GaAs and AlGaAs.