The nonlinear Rashba effect in Hg_0.77Cd_0.23Te inversion layers probed by weak antilocalization analysis

The Rashba spin-orbit interaction of the two-dimensional electron gas with high mobility in the inversion layer of p-type Hg_0.77Cd _0.23Te is investigated by magnetotransport measurements. Both the Rashba spin splitting and Rashba coefficient are extracted by analysis of the weak anti-localization effect using the Golub model. It is found that both the splitting and coefficient increase with increasing electron density (∼3.0-6.0 × 10¹⁵ m^-2), i.e., with the gate voltage. A self-consistent Schrodinger-Poisson calculation is performed and suggests that the nonlinear Rashba effect caused by the weakening of interband coupling, especially at high electron density, dominates this system.