微波场下自旋偏压驱动的量子点输运特性  

Transport Properties of Quantum Dot Driven by Spin Bias in Microwave Field

作　　者：段亚南[1] 李志坚[1] 

机构地区：[1]山西大学理论物理研究所,山西太原030006

出　　处：《山西大学学报（自然科学版）》2010年第2期215-218,共4页Journal of Shanxi University(Natural Science Edition)

基　　金：山西省青年(自然)科学基金(2007021001;2008011001-2);国家自然科学基金(10774094)

摘　　要：采用非平衡态格林函数方法,研究了外磁场、微波场对自旋偏压驱动量子点输运特性的影响.数值结果表明:外磁场破坏量子点能级的自旋简并,相应自旋流的共振峰劈裂,电荷流不为零,不能获得纯自旋流;微波场作用下,量子点会有更多的隧穿通道,产生了许多的边带峰,特别是强微波场作用下多光子过程起了重要作用.The effects of external magnetic field and time-varying microwave field on transport properties ot quantum dot driven by spin bias voltage are investigated by means of nonequilibrium Green function method. The numerical results show that the resonance peaks of spin current split and the pure spin current disappears due to that magnetic field destroying the spin degeneration of energy in quantum dot. When the time-dependent sine microwave filed is imposed,the quantum dot has more effective tunneling channels be- cause electrons can absorb the photons. As a result,many side-peaks appear in the current curve. The multiple-photon processes become more important as the intensity of microwave field becomes stronger.

关 键 词：微波场 自旋偏压 电荷流 纯自旋流 

分 类 号：O413[理学—理论物理]