title: The limit spin current in a time-dependent Rashba spin-orbit coupling system.
abstract: The generation of spin current in a one dimensional electron gas (1DEG) system is studied, where the Rashba spin-orbit coupling (RSOC) is modulated by a time-varying gate voltage. With a simple unitary transformation, we show the appearance of an additional spin-dependent potential which results in a spin-dependent effective electric field. We include the scattering interaction by taking a relaxation approximation. The formula for the induced spin current is derived, the limit  value accessible by time-varying RSOC is obtained and the order of magnitude is estimated. We find that the maximum of a pulsed spin current can reach that limit value. The results in 1DEG are extended to 2DEG. In addition, we study the spin current in a metal-quantum dot-metal system.
authors: Institute of Physics, Chinese Academy of Sciences, Beijing 100190, People's Republic of China.
authors: Shu-feng
authors: SF
authors: Zhang
authors: Wei
authors: W
authors: Zhu
mesh_terms: D003198:Computer Simulation; D004574:Electromagnetic Fields; D008670:Metals / Q000737:chemistry*; D008956:Models, Chemical; D008958:Models, Molecular
chemical_list: D008670:Metals