中国物理B ›› 2015, Vol. 24 ›› Issue (2): 27401-027401.doi: 10.1088/1674-1056/24/2/027401

• CONDENSED MATTER: ELECTRONIC STRUCTURE, ELECTRICAL, MAGNETIC, AND OPTICAL PROPERTIES • 上一篇    下一篇

Evolution of the 128-cm-1 Raman phonon mode with temperature in Ba(Fe1-xCox)2As 2 (x = 0.065 and 0.2)

杨彦兴a b, Gallais Yannb, 方之颢a, 石兢a, 熊锐a   

  1. a School of Physics and Technology, Wuhan University, Wuhan 430072, China;
    b Laboratoire Matériaux et Phénomenes Quantiques (UMR 7162 CNRS), Université Paris Diderot-Paris 7, Bâtiment Condorcet, 75205 Paris Cedex 13, France
  • 收稿日期:2014-09-24 修回日期:2014-10-10 出版日期:2015-02-05 发布日期:2015-02-05
  • 基金资助:
    Project supported by the Agence Nationale de la Recherche through Grant PNICTIDES.

Evolution of the 128-cm-1 Raman phonon mode with temperature in Ba(Fe1-xCox)2As 2 (x = 0.065 and 0.2)

Yang Yan-Xing (杨彦兴)a b, Gallais Yannb, Fang Zhi-Hao (方之颢)a, Shi Jing (石兢)a, Xiong Rui (熊锐)a   

  1. a School of Physics and Technology, Wuhan University, Wuhan 430072, China;
    b Laboratoire Matériaux et Phénomenes Quantiques (UMR 7162 CNRS), Université Paris Diderot-Paris 7, Bâtiment Condorcet, 75205 Paris Cedex 13, France
  • Received:2014-09-24 Revised:2014-10-10 Online:2015-02-05 Published:2015-02-05
  • Contact: Xiong Rui E-mail:xiongrui@whu.edu.cn
  • Supported by:
    Project supported by the Agence Nationale de la Recherche through Grant PNICTIDES.

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摘要： We report electronic Raman scattering measurements on Ba(Fe1-xCox)2As2 (x = 0.065 and 0.2) single crystals with Raman shifts from 9 cm-1 up to 600 cm-1 in the symmetry of B1g with respect to 1 Fe unit cell. When the crystals are cooled down, the evident quasielastic peaks of Raman spectra occur only in the crystal with x = 0.065, which is due to the contribution of orbital ordering between xz and yz Fe 3d orbitals, as we reported in another work. Here, we analyze the Eg phonon at 128 cm-1, which has the same function form of its Raman tensors as those of xz and yz Fe 3d orbitals in these two crystals respectively. Unlike their electronic continuums, no anomalies are found in the Eg phonons of these two samples, which simply follows the expressions corresponding to the anharmonic phonon decay into acoustic phonons with the same frequencies and opposite momenta. Our results indicate that the structural and magnetic phase transition might be completely suppressed by chemical doping and there is not any indication of coupling between charge nematicity and Eg phonon mode from our experimental results, which is consistent with the results in our previous work.

关键词: Raman scattering, iron-based superconductor, phonon mode

Abstract: We report electronic Raman scattering measurements on Ba(Fe1-xCox)2As2 (x = 0.065 and 0.2) single crystals with Raman shifts from 9 cm-1 up to 600 cm-1 in the symmetry of B1g with respect to 1 Fe unit cell. When the crystals are cooled down, the evident quasielastic peaks of Raman spectra occur only in the crystal with x = 0.065, which is due to the contribution of orbital ordering between xz and yz Fe 3d orbitals, as we reported in another work. Here, we analyze the Eg phonon at 128 cm-1, which has the same function form of its Raman tensors as those of xz and yz Fe 3d orbitals in these two crystals respectively. Unlike their electronic continuums, no anomalies are found in the Eg phonons of these two samples, which simply follows the expressions corresponding to the anharmonic phonon decay into acoustic phonons with the same frequencies and opposite momenta. Our results indicate that the structural and magnetic phase transition might be completely suppressed by chemical doping and there is not any indication of coupling between charge nematicity and Eg phonon mode from our experimental results, which is consistent with the results in our previous work.

Key words: Raman scattering, iron-based superconductor, phonon mode

中图分类号:  (Pnictides and chalcogenides)

  • 74.70.Xa
78.30.-j (Infrared and Raman spectra) 74.25.nd (Raman and optical spectroscopy)