嵌入单量子点Aharonov-Bohm环中的近藤效应  

Kondo effect in the quantum dot embedded in the Aharonov-Bohm ring

作　　者：吴绍全[1] 孙威立[1] 余万伦[2] 王顺金[3] 

机构地区：[1]四川师范大学物理系,成都610068 [2]成都信息工程学院,成都610030 [3]四川大学物理系,成都610034

出　　处：《物理学报》2005年第6期2910-2917,共8页Acta Physica Sinica

基　　金：四川省应用基础研究基金资助项目(批准号:02GY029188);四川省教育厅自然科学研究基金资助项目(批准号:2003A0780)资助的课题.~~

摘　　要：使用单杂质的Ansderson模型,从理论上研究了一个嵌入单量子点Aharonov Bohm环系统处在近藤区时的基态性质,并用slave boson平均场方法求解了该模型.结果表明在零温,当介观环内电子平均能级间隔大于近藤关联能时,系统内仍然存在一个被减弱了的近藤效应;系统的基态性质依赖于系统的宇称和环的大小;而尺寸效应和近藤屏蔽效应的共存导致了系统丰富的物理性质.同时,可以通过测量介观环中的持续电流和杂质磁化率,达到探测近藤屏蔽云的目的.The properties of the ground state of a closed dot-ring system with a magnetic flux in the Kondo regime are studied theoretically by means of a one-impurity Anderson Hamiltonian. The Hamiltonian is solved by means of the Slave-Boson mean-field theory. It is shown that at T = 0, a suppressed Kondo effect exists in this system even when the mean level spacing of electrons in the ring is larger than the bulk Kondo temperature; the physical quantities of this system depend sensitively on both the parity of the system and the size of the ring; the rich physical behaviors of this system can attribute to the coexistence of both the finite-size effect and the Kondo screening effect in this system. It is also possible to detect the Kondo screening cloud by measuring the persistent current or the zero-field impurity susceptibility chi(imp) directly in future experiments.

关 键 词：持续电流 杂质磁化率 宇称效应 近藤效应 近藤屏蔽云 量子点 

分 类 号：O471.1[理学—半导体物理] O474[理学—物理]