Electric field effect on electron spin splitting in SiGe/Si quantum wells

M. O. Nestoklon, E. L. Ivchenko, J. -M. Jancu, P. Voisin

Published 2007-12-12, updated 2007-12-21Version 2

Effect of electric field on spin splitting in SiGe quantum wells (QWs) has been studied theoretically. Microscopical calculations of valley and spin splittings are performed in the effective $sp^3d^5s^*$ tight-binding model. The splittings oscillate as a function of the QW width due to inter-valley reflection of the electron wave off the interfaces. In accordance with the symmetry considerations additional electric-field-induced terms appear in the electron spin-dependent Hamiltonian. The oscillations of splitting are suppressed in rather low electric fields. The tight-binding calculations have been analyzed by using the envelope function approach extended to asymmetrical QWs.