Large Rashba spin–orbit splitting in gate controlled n-type modulation doped HgTe/Hg0.3Cd0.7−xMnxTe quantum wells

We report on Rashba spin–orbit splitting in a series of gated n-type HgTe/Hg0.3Cd0.7−xMnxTe quantum wells with an inverted band structure. By analyzing the gate-voltage-dependent beating pattern observed in the Shubnikov–de Haas oscillations, we determine the gate voltage dependence of the spin–orbit coupling parameter β, which can be tuned by a factor of about 5 in the narrow spacer sample. Our experimental data and its analysis show that the Hg0.3Cd0.7−xMnxTe layer strongly enhances the spin–orbit splitting, when close enough to the two-dimensional electron gas.