Study of Rashba spin splitting and intersubband spin-orbit coupling effect in AlGaN/GaN quantum wells

Rashba spin splitting coefficients for the first two subbands alpha(1), alpha(2) and intersubband spin-orbit coupling coefficient eta(12) are obtained by projecting the characteristic equation into the subspace of conduction band. Then Schrodinger and the Poisson equations are solved self-consistently to calculate alpha(1), alpha(2) and eta(12) under different gate voltages. Then contributions to the spin-orbit coupling coefficients from the well, the left and the right heterointerfaces and the left and the right barriers of the quantum well are discussed. Resulsts show that the spin-orbit coupling coefficient can be modulated by the gate voltage, and the intersubband spin-orbit coupling coefficients calculated here are a little smaller than the Rashba coefficients alpha(1), alpha(2), but they are basically of the same order.