Scattering mechanisms in state-of-the-art GaAs/AlGaAs quantum wells
Yi Huang, B. I. Shklovskiǐ, M. A. Zudov
Abstract
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, ${n}_{e}\ensuremath{\lesssim}1\ifmmode\times\else\texttimes\fi{}{10}^{11}\phantom{\rule{4pt}{0ex}}{\mathrm{cm}}^{\ensuremath{-}2}$, both transport and quantum mobility are limited by unintentional background impurities and follow a power-law dependence, $\ensuremath{\propto}{n}_{e}^{\ensuremath{\alpha}}$, with $\ensuremath{\alpha}\ensuremath{\approx}0.85$. Our predictions for quantum mobility are in reasonable agreement with an estimate obtained from the resistivity at filling factor $\ensuremath{\nu}=1/2$ in a sample of Y. J. Chung et al. with ${n}_{e}=1\ifmmode\times\else\texttimes\fi{}{10}^{11}\phantom{\rule{4pt}{0ex}}{\mathrm{cm}}^{\ensuremath{-}2}$. 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.