Eur. Phys. J. B (2012) 85: 305
https://doi.org/10.1140/epjb/e2012-30335-4

Regular Article

Spin-dependent electron transport in a Rashba quantum wire with rough edges

¹ School of Computer, Jiangxi University of Traditional Chinese Medicine, Nanchang 330004, P.R. China
² Institute for Advanced Study, Nanchang University, Nanchang 330031, P.R. China
³ Department of Physics and Key Laboratory for Low-Dimensional Quantum Structures and Manipulation (Ministry of Education), Hunan Normal University, Changsha 410081, P.R. China

^a e-mail: nhliu@ncu.edu.cn

Received: 20 April 2012
Received in final form: 1 July 2012
Published online: 10 September 2012

Abstract

We investigate theoretically the spin-dependent electron transport in a Rashba quantum wire with rough edges. The charge and spin conductances are calculated as function of the electron energy and wire length by adopting the spin-resolved lattice Green function method. For a single disordered Rashba wire, it is found that the charge conductance quantization is destroyed by the edge disorder. However, a nonzero spin conductance can be generated and its amplitude can be manipulated by varying the wire length, which is attributed to the broken structure symmetries and the spin-dependent quantum interference induced by the rough boundaries. For a large ensemble of disordered Rashba wires, the average charge conductance decreases monotonically, however, the average spin conductance increases to a maximum value and then decreases, with increasing wire length. Further study shows that the influence of the rough edges on the charge and spin conductances can be eliminated by applying a perpendicular magnetic field to the wire. In addition, a very large magnitude of the spin conductance can be achieved when the electron energy lies between the two thresholds of each pair of subbands. These findings may not only benefit to further apprehend the transport properties of the Rashba low-dimensional systems but also provide some theoretical instructions to the application of spintronics devices.