中国物理B ›› 2006, Vol. 15 ›› Issue (4): 735-749.doi: 10.1088/1009-1963/15/4/014

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Existence of the transverse relaxation time in optically excited bulk semiconductors

张海潮1, 王育竹1, 林位株2   

  1. (1)Laboratory for Quantum Optics, Shanghai Institute of Optics and Fine Mechanics,Chinese Academy of Sciences, Shanghai 201800, China; (2)State Key Laboratory of Optoelectronic Materials and Technologies, Zhongshan University,Guangzhou 510275, China
  • 收稿日期:2005-10-21 修回日期:2006-01-11 出版日期:2006-04-20 发布日期:2006-04-20
  • 基金资助:
    Project supported by the State Key Program of Basic Research of China (Grant No 2001CB309307), and the National Natural Science Foundation of China (Grant Nos 10474105,10274107 and 10334050).

Existence of the transverse relaxation time in optically excited bulk semiconductors

Zhang Hai-Chao (张海潮)a, Lin Wei-Zhu (林位株)b, Wang Yu-Zhu (王育竹)a   

  1. a Laboratory for Quantum Optics, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800, China; b State Key Laboratory of Optoelectronic Materials and Technologies, Zhongshan University, Guangzhou 510275, China
  • Received:2005-10-21 Revised:2006-01-11 Online:2006-04-20 Published:2006-04-20
  • Supported by:
    Project supported by the State Key Program of Basic Research of China (Grant No 2001CB309307), and the National Natural Science Foundation of China (Grant Nos 10474105,10274107 and 10334050).

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摘要： Two basic types of depolarization mechanisms, carrier-carrier (CC) and carrier-phonon (CP) scattering, are investigated in optically excited bulk semiconductors (3D), in which the existence of the transverse relaxation time is proven based on the vector property of the interband transition matrix elements. The dephasing rates for both CC and CP scattering are determined to be equal to one half of the total scattering-rate-integrals weighted by the factors (1-\cos\chi), where \chi are the scattering angles. Analytical expressions of the polarization dephasing due to CC scattering are established by using an uncertainty broadening approach, and analytical ones due to both the polar optical-phonon and non-polar deformation potential scattering (including inter-valley scattering) are also presented by using the sharp spectral functions in the dephasing rate calculations. These formulas, which reveal the trivial role of the Coulomb screening effect in the depolarization processes, are used to explain the experimental results at hand and provide a clear physical picture that is difficult to extract from numerical treatments.

关键词: ultrafast dephasing, carrier-carrier scattering, carrier-phonon scattering

Abstract: Two basic types of depolarization mechanisms, carrier-carrier (CC) and carrier-phonon (CP) scattering, are investigated in optically excited bulk semiconductors (3D), in which the existence of the transverse relaxation time is proven based on the vector property of the interband transition matrix elements. The dephasing rates for both CC and CP scattering are determined to be equal to one half of the total scattering-rate-integrals weighted by the factors (1-$\cos\chi$), where $\chi$ are the scattering angles. Analytical expressions of the polarization dephasing due to CC scattering are established by using an uncertainty broadening approach, and analytical ones due to both the polar optical-phonon and non-polar deformation potential scattering (including inter-valley scattering) are also presented by using the sharp spectral functions in the dephasing rate calculations. These formulas, which reveal the trivial role of the Coulomb screening effect in the depolarization processes, are used to explain the experimental results at hand and provide a clear physical picture that is difficult to extract from numerical treatments.

Key words: ultrafast dephasing, carrier-carrier scattering, carrier-phonon scattering

中图分类号:  (Birefringence)

  • 78.20.Fm
72.10.Di (Scattering by phonons, magnons, and other nonlocalized excitations) 72.20.Jv (Charge carriers: generation, recombination, lifetime, and trapping) 73.50.Gr (Charge carriers: generation, recombination, lifetime, trapping, mean free paths)