Mobility in excess of $10^6$ cm${}^2$/Vs in InAs quantum wells grown on lattice mismatched InP substrates

Abstract

InAs-based two-dimensional electron systems grown on lattice mismatched InP substrates offer a robust platform for the pursuit of topologically protected quantum computing. We investigated strained composite quantum wells of In${}_{0.75}$Ga${}_{0.25}$As/InAs/In${}_{0.75}$Ga${}_{0.25}$As with In${}_{0.75}$Al${}_{0.25}$As barriers. By optimizing the widths of the In${}_{0.75}$Ga${}_{0.25}$As layers, the In${}_{0.75}$Al${}_{0.25}$As barrier, and the InAs quantum well we demonstrate mobility in excess of $1 \times 10^{6}\,$cm$^{2}/$Vs. Mobility vs. density data indicates that scattering is dominated by a residual three dimensional distribution of charged impurities. We extract the Rashba parameter and spin-orbit length as important material parameters for investigations involving Majorana zero modes.