Spin-orbit interactions in semiconductor superlattice.

• Semiconductor superlattice can generate larger spin splitting than single asymmetric quantum well, resulting in desirable spin polarization. • Spin orientations of electrons of semiconductor superlattice may not change during transport processes, resulting in long spin relaxation time. • One superlattice structure can realize two functions, acting as a spin field effect transistor and a spin filter. • Spin splitting of some sublevels does not vary with structure parameters, reducing the demand for accuracy in quantum wells size. • Using semiconductor superlattice will contribute to the detection of spin related phenomenon and promote the progress of spintronic devices. The purpose of this paper is to theoretically investigate the spin-orbit interactions of common semiconductor superlattices. Spin splitting and spin-orbit interaction coefficients are calculated based on interactions between the interface-related-Rashba effect and Dresselhaus effect. Semiconductor superlattice shows a series of specific characteristics in spin splitting as follows. The spin splitting of the superlattice structure is greater than that of a single quantum well, contributing to significant spin polarization, spin filtering, and convenient manipulation of spintronic devices. The spin splitting of some superlattice structures does not change with variation of the size of some constituent quantum wells, reducing the requirements for accuracy in the size of quantum wells. The total spin splitting of lower sub-levels of some superlattice can be designed to be zero, realizing a persistent spin helix effect and long spin relaxation time, however, the total spin splitting of higher sub-levels is still appreciable, contributing to desirable spin polarization. These results demonstrate that one superlattice structure can realize two functions, acting as a spin field effect transistor and a spin filter. [ABSTRACT FROM AUTHOR]