中国物理B ›› 2012, Vol. 21 ›› Issue (5): 57302-057302.doi: 10.1088/1674-1056/21/5/057302

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Plasmons in a free-standing nanorod with a two-dimensional parabolic quantum well caused by surface states

宋亚峰1,吕燕伍2,文伟3,刘祥林1,杨少延1,朱勤生1,王占国1   

  1. 1. Key Laboratory of Semiconductor Materials Science, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China;
    2. Department of Physics, Beijing Jiaotong University, Beijing 100044, China;
    3. State Key Laboratory for Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China
  • 收稿日期:2011-10-18 修回日期:2012-04-27 出版日期:2012-04-01 发布日期:2012-04-01
  • 基金资助:
    Project supported by the National Natural Science Foundation of China (Grant Nos. 60976008, 61006004, 61076001, and 10979507), the National Basic Research Program of China (Grant No. A000091109-05), and the National High Technology Research and Development Program of China (Grant No. 2011AA03A101)

Plasmons in a free-standing nanorod with a two-dimensional parabolic quantum well caused by surface states

Song Ya-Feng(宋亚峰)a), Lü Yan-Wu(吕燕伍)b), Wen Wei(文伟)c), Liu Xiang-Lin(刘祥林)a), Yang Shao-Yan(杨少延)a), Zhu Qin-Sheng(朱勤生)a)†, and Wang Zhan-Guo(王占国)a)   

  1. a. Key Laboratory of Semiconductor Materials Science, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China;
    b. Department of Physics, Beijing Jiaotong University, Beijing 100044, China;
    c. State Key Laboratory for Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China
  • Received:2011-10-18 Revised:2012-04-27 Online:2012-04-01 Published:2012-04-01
  • Supported by:
    Project supported by the National Natural Science Foundation of China (Grant Nos. 60976008, 61006004, 61076001, and 10979507), the National Basic Research Program of China (Grant No. A000091109-05), and the National High Technology Research and Development Program of China (Grant No. 2011AA03A101)

摘要: The collective charge density excitations in a free-standing nanorod with a two-dimensional parabolic quantum well are investigated within the framework of Bohm--Pine's random-phase approximation in the two-subband model. The new simplified analytical expressions of the Coulomb interaction matrix elements and dielectric functions are derived and numerically discussed. In addition, the electron density and temperature dependences of dispersion features are also investigated. We find that in the two-dimensional parabolic quantum well, the intrasubband upper branch is coupled with the intersubband mode, which is quite different from other quasi-one-dimensional systems like a cylindrical quantum wire with an infinite rectangular potential. In addition, we also find that higher temperature results in the intersubband mode (with an energy of 12 meV (~ 3 THz)) becoming totally damped, which agrees well with the experimental results of Raman scattering in the literature. These interesting properties may provide useful references to the design of free-standing nanorod based devices.

关键词: plasmons, two-dimensional parabolic quantum well, terahertz nanodevices, nanorod

Abstract: The collective charge density excitations in a free-standing nanorod with a two-dimensional parabolic quantum well are investigated within the framework of Bohm--Pine's random-phase approximation in the two-subband model. The new simplified analytical expressions of the Coulomb interaction matrix elements and dielectric functions are derived and numerically discussed. In addition, the electron density and temperature dependences of dispersion features are also investigated. We find that in the two-dimensional parabolic quantum well, the intrasubband upper branch is coupled with the intersubband mode, which is quite different from other quasi-one-dimensional systems like a cylindrical quantum wire with an infinite rectangular potential. In addition, we also find that higher temperature results in the intersubband mode (with an energy of 12 meV (~ 3 THz)) becoming totally damped, which agrees well with the experimental results of Raman scattering in the literature. These interesting properties may provide useful references to the design of free-standing nanorod based devices.

Key words: plasmons, two-dimensional parabolic quantum well, terahertz nanodevices, nanorod

中图分类号:  (Collective excitations (including excitons, polarons, plasmons and other charge-density excitations))

  • 73.20.Mf
73.21.Hb (Quantum wires)