中国物理B ›› 2007, Vol. 16 ›› Issue (7): 2106-2110.doi: 10.1088/1009-1963/16/7/051

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Photon-assisted electronic structure and transport for a quantum dot

周光辉1, 廖文虎2, 高钦翔2   

  1. (1)Department of Physics, Hunan Normal University, Changsha 410081, China;International Center for Materials Physics, Chinese Academy of Sciences, Shenyang 110015, China; (2)Department of Physics, Zunyi Normal College, Zunyi 563002, China
  • 收稿日期:2006-11-24 修回日期:2006-12-03 出版日期:2007-07-20 发布日期:2007-07-04
  • 基金资助:
    Project supported by the National Natural Science Foundation of China (Grant No 10574042) and the Guizhou Provincial Science and Technology Foundation of China (Grant No 20052088).

Photon-assisted electronic structure and transport for a quantum dot

Liao Wen-Hu(廖文虎)a), Gao Qin-Xiang(高钦翔)a), and Zhou Guang-Hui(周光辉)b)c)†   

  1. a Department of Physics, Zunyi Normal College, Zunyi 563002, Chinab Department of Physics, Hunan Normal University, Changsha 410081, China; c International Center for Materials Physics, Chinese Academy of Sciences, Shenyang 110015, China
  • Received:2006-11-24 Revised:2006-12-03 Online:2007-07-20 Published:2007-07-04
  • Supported by:
    Project supported by the National Natural Science Foundation of China (Grant No 10574042) and the Guizhou Provincial Science and Technology Foundation of China (Grant No 20052088).

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摘要： This paper investigates theoretically the electronic structure and transport of a two-level quantum dot irradiated under a strong laser field at low temperatures. Using the method of Keldysh equation of motion for nonequilibrium Green functions, it examines the time-averaged density of states and conductance for the system with photon polarization parallel with and perpendicular to the tunnelling current direction respectively. It is demonstrated that, by analysing some numerical examples, more photon sidebands resonance states and multi- and single-photon transitions are found when diagonal matrix elements dominate the interaction, while the electronic transitions due to multiphoton absorption are more or less suppressed when off-diagonal interaction dominates.

关键词: quantum dot, laser field, density of states, nonequilibrium Green functions

Abstract: This paper investigates theoretically the electronic structure and transport of a two-level quantum dot irradiated under a strong laser field at low temperatures. Using the method of Keldysh equation of motion for nonequilibrium Green functions, it examines the time-averaged density of states and conductance for the system with photon polarization parallel with and perpendicular to the tunnelling current direction respectively. It is demonstrated that, by analysing some numerical examples, more photon sidebands resonance states and multi- and single-photon transitions are found when diagonal matrix elements dominate the interaction, while the electronic transitions due to multiphoton absorption are more or less suppressed when off-diagonal interaction dominates.

Key words: quantum dot, laser field, density of states, nonequilibrium Green functions

中图分类号:  (Quantum dots)

  • 73.21.La
61.80.Ba (Ultraviolet, visible, and infrared radiation effects (including laser radiation)) 73.40.Gk (Tunneling) 73.63.Kv (Quantum dots)