中国物理B ›› 2006, Vol. 15 ›› Issue (9): 2102-2107.doi: 10.1088/1009-1963/15/9/033

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Effect of electric field on the electronic spectrum and the persistent current of a quantum ring with two electrons

鲍诚光1, 吴洪2   

  1. (1)Center of Theoretical Nuclear Physics, National Laboratory of Heavy Ion Collisions, Lanzhou 730000, China; (2)Department of Physics, School of Science, Jimei University, Xiamen 361021, China
  • 收稿日期:2006-01-15 修回日期:2006-05-18 出版日期:2006-09-20 发布日期:2006-09-20
  • 基金资助:
    Project supported by the National Natural Science Foundation of China (Grant No 10574163), the Center of Theoretical Nuclear Physics, National Laboratory of Heavy Ion Collisions, Lanzhou, China.

Effect of electric field on the electronic spectrum and the persistent current of a quantum ring with two electrons

Wu Hong(吴洪)b)† and Bao Cheng-Guang(鲍诚光)a)   

  1. a Center of Theoretical Nuclear Physics, National Laboratory of Heavy Ion Collisions, Lanzhou 730000, China; b Department of Physics, School of Science, Jimei University, Xiamen 361021, China
  • Received:2006-01-15 Revised:2006-05-18 Online:2006-09-20 Published:2006-09-20
  • Supported by:
    Project supported by the National Natural Science Foundation of China (Grant No 10574163), the Center of Theoretical Nuclear Physics, National Laboratory of Heavy Ion Collisions, Lanzhou, China.

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摘要： The effect of an electric field E on a narrow quantum ring that contains two electrons and is threaded by a magnetic flux B has been investigated. Localization of the electronic distribution and suppression of the Aharonov--Bohm oscillation (ABO) are found in the two-electron ring, which are similar to those found in a one-electron ring. However, the period of ABO in a two-electron ring is reduced by half compared with that in a one-electron ring. Furthermore, during the variation of B, the persistent current of the ground state may undergo a sudden change in sign. This change is associated with a singlet--triplet transition and has no counterpart in one-electron rings. For a given E, there exists a threshold of energy. When the energy of the excited state exceeds the threshold, the localization would disappear and the ABO would recover. The value of the threshold is proportional to the magnitude of E. Once the threshold is exceeded, the persistent current is much stronger than the current of the ground state at E=0.

关键词: quantum ring, electronic structure, effect of electric field

Abstract: The effect of an electric field E on a narrow quantum ring that contains two electrons and is threaded by a magnetic flux B has been investigated. Localization of the electronic distribution and suppression of the Aharonov--Bohm oscillation (ABO) are found in the two-electron ring, which are similar to those found in a one-electron ring. However, the period of ABO in a two-electron ring is reduced by half compared with that in a one-electron ring. Furthermore, during the variation of B, the persistent current of the ground state may undergo a sudden change in sign. This change is associated with a singlet--triplet transition and has no counterpart in one-electron rings. For a given E, there exists a threshold of energy. When the energy of the excited state exceeds the threshold, the localization would disappear and the ABO would recover. The value of the threshold is proportional to the magnitude of E. Once the threshold is exceeded, the persistent current is much stronger than the current of the ground state at E=0.

Key words: quantum ring, electronic structure, effect of electric field

中图分类号:  (Linear defects: dislocations, disclinations)

  • 61.72.Lk
61.72.Hh (Indirect evidence of dislocations and other defects (resistivity, slip, creep, strains, internal friction, EPR, NMR, etc.)) 61.72.Bb (Theories and models of crystal defects)