嵌入单量子点Aharonov-Bohm环中的尺寸和近藤屏蔽效应  

Finite-size effect and Kondo screening effect in the quantum dot embedded in the Aharonov-Bohm Ring

作　　者：尹析明[1] 吴绍全[2] 

机构地区：[1]成都纺织高等专科学校,成都611731 [2]四川师范大学物理与电子工程学院,成都610068

出　　处：《四川大学学报（自然科学版）》2009年第3期677-683,共7页Journal of Sichuan University(Natural Science Edition)

基　　金：四川省应用基础研究基金(2006J13-155);四川省教育厅自然科学研究基金(2008A069)

摘　　要：使用单杂质的Ansderson模型,我们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。我们的结果表明: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 m 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 behavior of this system can attributed 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 Zimp 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 

分 类 号：O413.2[理学—理论物理]