中国物理B ›› 2004, Vol. 13 ›› Issue (4): 510-515.doi: 10.1088/1009-1963/13/4/017

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Finite-size effect and Kondo screening effect in an A-B ring with a quantum dot

余万伦1, 孙威立2, 吴绍全3, 王顺金4   

  1. (1)Chengdu Institute of Information and Technology, Chengdu 610030, China; (2)Department of Physics, Sichuan Normal University, Chengdu 610068, China; (3)Department of Physics, Sichuan Normal University, Chengdu 610068, China; Institute of Modern Physics, Southwest Jiaotong University, Chengdu 610031, China; (4)Institute of Modern Physics, Southwest Jiaotong University, Chengdu 610031, China
  • 收稿日期:2003-05-20 修回日期:2003-09-20 出版日期:2004-04-22 发布日期:2004-04-20
  • 基金资助:
    Project supported by the Funds for Major Basic Research Project of Sichuan Province (Grant No 02GY029-188), and the Natural Science Foundation of the Committee of Education of Sichuan Province (Grant No 2003A078).

Finite-size effect and Kondo screening effect in an A-B ring with a quantum dot

Wu Shao-Quan (吴绍全)ab, Wang Shun-Jin (王顺金)b, Yu Wan-Lun (余万伦)a, Sun Wei-Li (孙威立)c    

  1. a Department of Physics, Sichuan Normal University, Chengdu 610068, China; b Institute of Modern Physics, Southwest Jiaotong University, Chengdu 610031, China; c Chengdu Institute of Information and Technology, Chengdu 610030, China
  • Received:2003-05-20 Revised:2003-09-20 Online:2004-04-22 Published:2004-04-20
  • Supported by:
    Project supported by the Funds for Major Basic Research Project of Sichuan Province (Grant No 02GY029-188), and the Natural Science Foundation of the Committee of Education of Sichuan Province (Grant No 2003A078).

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摘要： 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 depend sensitively on both the parity of the system and the size of the ring; the rich physical behaviour can be attributed to the coexistence of both the finite-size effect and the Kondo screening effect. It is also possible to detect the Kondo screening cloud by measuring the persistent current or the zero field impurity susceptibility χ_{imp} directly in future experiments.

关键词: finite-size effect, Kondo screening effect, A-B ring, quantum dot

Abstract: 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 depend sensitively on both the parity of the system and the size of the ring; the rich physical behaviour can be attributed to the coexistence of both the finite-size effect and the Kondo screening effect. It is also possible to detect the Kondo screening cloud by measuring the persistent current or the zero field impurity susceptibility $\chi_{\rm imp}$ directly in future experiments.

Key words: finite-size effect, Kondo screening effect, A-B ring, quantum dot

中图分类号:  (Scattering by point defects, dislocations, surfaces, and other imperfections (including Kondo effect))

  • 72.10.Fk
71.55.-i (Impurity and defect levels) 73.63.Kv (Quantum dots) 72.30.+q (High-frequency effects; plasma effects)