Lattice and electronic anomalies of CaFe2As2 studied by Raman spectroscopy

被引：62
作者：
Choi, K. -Y. [1 ]
Wulferding, D. [2 ]
Lemmens, P. [2 ]
Ni, N. [3 ,4 ]
Bud'ko, S. L. [3 ,4 ]
Canfield, P. C. [3 ,4 ]
机构：
[1] Chung Ang Univ, Dept Phys, Seoul 156756, South Korea
[2] Tech Univ Carolo Wilhelmina Braunschweig, Inst Condensed Matter Phys, D-38106 Braunschweig, Germany
[3] Iowa State Univ, Dept Phys & Astron, Ames, IA 50011 USA
[4] Iowa State Univ, US DOE, Ames Lab, Ames, IA 50011 USA
来源：
PHYSICAL REVIEW B | 2008年 / 78卷 / 21期
关键词：
calcium compounds; electronic density of states; iron compounds; light scattering; phonons; Raman spectra; solid-state phase transformations; spectral line breadth;
D O I：
10.1103/PhysRevB.78.212503
中图分类号：
T [工业技术];
学科分类号：
08 ;
摘要：
We report inelastic light-scattering experiments on CaFe2As2 in the temperature range of 4-290 K. In in-plane polarizations two Raman-active phonon modes are observed at 189 and 211 cm(-1), displaying A(1g) and B-1g symmetries, respectively. Upon heating through the tetragonal-to-orthorhombic transition at about T-S=173 K, the B-1g phonon undergoes a discontinuous drop of frequency by 4 cm(-1), whereas the A(1g) phonon shows a suppression of the integrated intensity. Their linewidth increases strongly with increasing temperature and saturates above T-S. This suggests (i) a first-order structural phase transition and (ii) a drastic change in charge distribution within the FeAs plane through T-S.
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页数：4
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