Conduction-band spin splitting effects in staggered-bandgap structures

It is well understood that the two-fold energy degeneracy for spin-up and spin-down electrons regarding two dimensional electrons gas (2DEG) confined within a semiconductor heterostructure can be removed at zero magnetic fields (Bychkov, 1984). The splitting from the structure inversion asymmetry is described by the so-called Rashba term, H_R = plusmnalphak, where k is the wave vector and the coefficient alpha is proportional to the external electric field. The physical origin of Rashba effect is attributed to the spin-orbit (SO) interaction in semiconductor (Rashba, 2003).