SPIN TRANSPORT FOR A QUANTUM WIRE WITH WEAK DRESSELHAUS SPIN-ORBIT COUPLING

Abstract

We investigate theoretically the electron transport properties of a quantum wire (QW) non-adiabatically connected to two normal leads with weak Dresselhaus spin-orbit coupling (DSOC). Using the scattering matrix method and Landauer–Büttiker formula within the effective free-electron approximation, we have calculated the spin-dependent conductances G↑/↓ and spin polarization Pz of a hard-wall potential confined QW. It is demonstrated that regardless of the existence of DSOC G↑/↓ and Pz present oscillation structures near the subband edges of QW, and the number of quantized conductance plateaus is determined by the number of propagation modes in two leads. Moreover, the DSOC induces splitting of spin-up and spin-down conductance plateaus as well as the existence of spin polarization (Pz ≠ 0), and the enhancement of Dresselhaus strength destroys the conductance plateaus for the wide QW case. The above results indicate that the spin-dependent conductances and Pz are strongly dependent on the Dresselhaus strength which is the physical basis for spin transistor.