Spin polarization in quantum wires: Influence of Dresselhaus spin-orbit interaction and cross-section effects

Abstract

We examine the effects of the full Dresselhaus spin-orbit coupling on laterally confined quantum wire states. An analysis of the relative contributions due to linear, quadratic, and cubic Dresselhaus spin-orbit terms on the energy levels, spin splitting, and spin polarization has been carried out. The effects of wire cross-sectional geometry shapes on the electronic structure are explored. In particular we compared the results of semicylindrical and cylindrical confinements and have found important differences between the spin degeneracy of the ground-state level and the spin-polarization dependence on sign inversion of the free linear momentum quantum number along the wire axis. Different from other symmetries, in both cases here considered, the stronger spin-splitting effects come from the quadratic Dresselhaus term. We report ideal conditions for realization of spin-field filter devices based on symmetry properties of the spin splitting of the ground state in semicylindrical quantum wires.