Tunable B = 0 spin-splitting and its effect on the metallic behavior of GaAs two-dimensional holes

Abstract

A correlation between the zero magnetic-field spin-splitting and the metallic behavior was demonstrated. Spin-splitting of carriers at zero magnetic field in a 2D system is caused by spin-orbit interaction and by an inversion asymmetry of the confinement potential. In GaAs, the spin-splitting arises from the inversion asymmetries of the crystal structure and of the potential which confines the carriers to 2D. The asymmetry of the crystal structure is fixed, but the asymmetry of the confining potential, and the spin-splitting, can be changed by applying an electric field perpendicular to the 2D plane. The spin-splitting can be tuned while the density is kept constant and the metallic behavior of the 2D holes is related to the size of spin-splitting.