STUDY OF THE MODE SOFTENING IN NBSE2-2H

被引:10
作者
AYACHE, C
CURRAT, R
MOLINIE, P
机构
[1] ILL GRENOBLE,F-38042 GRENOBLE,FRANCE
[2] IMN,CNRS,F-44072 NANTES,FRANCE
来源
PHYSICA B | 1992年 / 180卷
关键词
D O I
10.1016/0921-4526(92)90750-M
中图分类号
O469 [凝聚态物理学];
学科分类号
070205 ;
摘要
We investigate the softening of the longitudinal SIGMA-1-phonon mode at wave vector Q = (a* /3, 0, 0) in the charge density wave compound NbSe2-2H. At room temperature, two branches belonging to the SIGMA-1 symmetry are observed at omega-1 approximately 10 meV and omega-2 approximately 5 meV, respectively. The energy of the lower branch starts to diminish only when the temperature is decreased below 100 K down to T(D) = 33 K, the temperature of the structural transition. The softening is complete within experimental uncertainty. The observed splitting of the two SIGMA-1 modes agrees with a prediction of a lattice dynamics calculation, based on a microscopic model taking into account the electron-phonon interaction. However experimental data show anomalous behaviour not accounted for by the theory.
引用
收藏
页码:333 / 335
页数:3
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