交换耦合双能级量子点的全计数统计  

Full Counting Statistics in Two-level Quantum Dot with Exchange Coupling

作　　者：赵美佳[1] 薛海斌[1] 聂一行[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）》2011年第2期223-226,共4页Journal of Shanxi University(Natural Science Edition)

基　　金：2010年山西省研究生优秀创新项目(批准号:20103001);国家自然科学基金(批准号:10774094)

摘　　要：基于粒子数分辨的量子主方程,研究了自旋交换耦合双能级量子点中的电子全计数统计,给出了平均电流、散粒噪声和偏斜度.库仑排斥和交换作用导致了平均电流中的小平台;散粒噪声和铁磁电极的极化率以及量子点与电极的不对称耦合密切相关.极化率和量子点电极不对称耦合越大,超泊松散粒噪声越容易出现.当两个自旋单态通道能级参与输运时散粒噪声会大大降低,而当两个自旋三重态通道能级同时参与输运时散粒噪声则会明显增大.The full counting statistics of electron transport is studied through a two-level quantum dot with exchange coupling based on an efficient particle-number-resolved quantum master equation,and the average current,shot noise and skewness are given.Coulomb repulsion and exchange interaction lead to small steps in the average current.The shot noise depends on the spin polarization of electrodes and asymmetry coupling between quantum dot and electrodes.The super-Poissonian noise occurs more easily for the large spin polarization and asymmetry coupling to the leads.When two spin-singlet channel levels participate simultaneously in the transport the shot noise decreases greatly,whereas two spin-triplet channel levels participate simultaneously in the transport that increases markedly.

关 键 词：主方程 全计数统计 散粒噪声 

分 类 号：O413[理学—理论物理]