Rashba spin splitting in inversion layers onp-type bulk InAs

The dependence of the spin-orbit interaction on electron density in inversion layers of metal-oxide-semiconductor field-effect transistors on p-type InAs is studied by magnetotransport at liquid-helium temperatures. We observe beating patterns in the Shubnikov–de Haas oscillations, which manifest the Rashba effect in a triangular surface potential. Taking subband nonparabolicity into account we evaluate Rashba parameters $\alpha$ that increase with electron density $n_s$ reaching a value $\alpha =3\mathrm{}\times {10}^{-11}\mathrm{eV}\mathrm{}\mathrm{m}$ at densities $n_s>~2.2\times {10}^{12}{\mathrm{cm}}^{-2}.$ Implications for the spin-dependent transport in spin-polarized high-electron-mobility transistors utilizing InAs quantum wells are discussed.