中国物理B ›› 2009, Vol. 18 ›› Issue (7): 2928-2932.doi: 10.1088/1674-1056/18/7/052

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Phonon spectra of La0.5Ca2MnO3

曹先胜, 陈长乐   

  1. Shaanxi Key Laboratory of Condensed Matter Structures and Properties, School of Science, Northwestern Polytechnical University, Xi'an 710072, China
  • 收稿日期:2008-07-30 修回日期:2008-12-25 出版日期:2009-07-20 发布日期:2009-07-20
  • 基金资助:
    Project supported by the National Natural Science Foundation of China (Grant No 60171034).

Phonon spectra of La0.5Ca2MnO3

Cao Xian-Sheng(曹先胜) and Chen Chang-Le(陈长乐)†   

  1. Shaanxi Key Laboratory of Condensed Matter Structures and Properties, School of Science, Northwestern Polytechnical University, Xi'an 710072, China
  • Received:2008-07-30 Revised:2008-12-25 Online:2009-07-20 Published:2009-07-20
  • Supported by:
    Project supported by the National Natural Science Foundation of China (Grant No 60171034).

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摘要： This paper presents a microscopic theory to explain different Raman modes of La0.5Ca0.5MnO3 based on the electronic Hamiltonian of the Kondo lattice model, which adds phonon interaction to the hybridization between the conduction electrons of the system and the l-electrons. The spectral density is calculated by the Green function technique of Zubarev at zero wave vector and in the low temperature limit. It finds that there are three Raman-active modes and the spectral densities of these modes are substantially influenced by model parameters such as the position of l-level (εJT), the effective electron--phonon coupling strength (g) and the hybridization parameter (v). Finally, the intensity changes of those peaks are investigated.

Abstract: This paper presents a microscopic theory to explain different Raman modes of La0.5Ca0.5MnO3 based on the electronic Hamiltonian of the Kondo lattice model, which adds phonon interaction to the hybridization between the conduction electrons of the system and the l-electrons. The spectral density is calculated by the Green function technique of Zubarev at zero wave vector and in the low temperature limit. It finds that there are three Raman-active modes and the spectral densities of these modes are substantially influenced by model parameters such as the position of l-level ($\varepsilon$JT), the effective electron--phonon coupling strength (g) and the hybridization parameter (v). Finally, the intensity changes of those peaks are investigated.

Key words: perovskite, Raman spectra

中图分类号:  (Phonon interactions)

  • 63.20.K-
63.20.D- (Phonon states and bands, normal modes, and phonon dispersion) 78.30.Hv (Other nonmetallic inorganics) 72.10.Fk (Scattering by point defects, dislocations, surfaces, and other imperfections (including Kondo effect))