Spin-orbit interaction in a two-dimensional electron gas in a InAs/AlSb quantum well with gate-controlled electron density

We present experiments on the tuning of the spin-orbit interaction in a two-dimensional electron gas in an asymmetric InAs/AlSb quantum well using a gate. The observed dependence of the spin splitting energy on the electron density can be attributed solely to the change in the Fermi wave vector. The spin-orbit interaction parameter $(\alpha \approx 0.6\times {10}^{-11}\mathrm{eV}\mathrm{}\mathrm{m})$ as such does not change significantly with electron density.