相互作用量子点系统中的场致自旋电流  

Spin current through a quantum dot in the presence of an oscillating magnetic field

作　　者：张平[1] 薛其坤[1] 谢心澄 

机构地区：[1]中国科学院物理研究所,国际量子结构中心,北京100080 [2]Department of Physics,Oklahoma State University,USA

出　　处：《物理》2004年第4期238-241,共4页Physics

基　　金：国家自然科学基金 (批准号 :60 0 2 14 0 3 ;10 13 40 3 0 ;10 1740 89);国家重点基础研究发展计划 (批准号 :G0 0 1CB3 0 95 ;2 0 0 2CB613 5 0 0 );美国NSF(批准号 :DMR -0 110 0 3 4)资助项目

摘　　要：从理论上研究了相互作用量子点在外部旋转磁场下的非平衡自旋输运性质 .研究结果表明 ,量子点中的相干自旋振荡可以导致自旋电流的产生 .当计入库仑关联相互作用后 ,近藤共振效应受外部进动磁场的影响很强 .特别是当磁场的进动频率与塞曼能移满足共振条件时 ,每个自旋近藤峰就会劈裂为两个自旋共振峰的叠加 .在低温强耦合区 ,这种近藤型共隧穿过程对自旋电流带来重要贡献 .Non-quilibrium spin transport through an interacting quantum dot is discussed. The coherent spin oscillations in the dot provide a source for generating spin current. In the interaction regime, the Kondo effect is influenced significantly by the presence of a precessing magnetic field. In particular, when the precession frequency is tuned to resonance between the spin-up and spin-down states of the dot, the Kondo singularity for each spin splits into a superposition of two resonance peaks. The Kondo-type cotunneling contribution is manifested by a large enhancement of the pumped spin current in the strong coupling, low temperature regime.

关 键 词：量子点 近藤共振 自旋电流 自旋电子学 量子计算 旋转磁场 

分 类 号：O572.2[理学—粒子物理与原子核物理]