Unusual polarization and temperature-dependent Raman response in Weyl semimetal NbIrTe4
Unusual polarization and temperature-dependent Raman response in Weyl semimetal NbIrTe4
复制标题
外尔半金属 NbIrTe4 中异常偏振和温度依赖性拉曼响应
DOI：
10.1016/j.ssc.2018.12.002
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发表时间：
2019-02-01
影响因子：
2.1
通讯作者：
Song, Li
中科院分区：
文献类型：
--
作者：
Chen, Haiping;Li, Yang;Song, Li
我们对层状Weyl半金属NbIrTe4在(002)晶体表面上的偏振和温度相关拉曼散射进行了系统研究，在平行和垂直偏振拉曼光谱几何结构下以后向散射方式，结合群论分析将单晶从0度旋转到360%记录了角度相关的拉曼峰强度，所有突出的拉曼峰都归属于A(1)和B-1振动模式，此外，我们证明了A(1) 模式拉曼峰值强度的角度依赖性相当不寻常，可以通过拉曼张量元素的复数值来解释，这可以追溯到该材料中的电子-声子相互作用。同时，通过研究随温度变化的拉曼散射光谱，研究了晶格非简谐振动行为，观察到随着温度从293 K降低到83 K，所有拉曼峰都表现出线性硬化行为，四个突出拉曼峰的温度系数表明了层状NbIrTe4晶体中晶格的非简谐性。
We carry out a systematic study of polarized- and temperature-dependent Raman scattering of layered Weyl semimetal NbIrTe4 on the (002) crystal surface, under parallel and perpendicular polarization Raman spectroscopy geometry in back scattering way, the angle-dependent Raman peaks intensity is recorded by rotating the single crystal from 0 degrees to 360% in combination with group theory analysis, all the prominent Raman peaks are assigned to A(1) and B-1 vibrational modes, moreover, we show that the angular dependence of Raman peak intensity of A(1) mode is rather unusual and can be explained by complex values for Raman tensor elements, which is traced back to electron-phonon interaction in this material. Meanwhile, lattice anharmonic vibrational behavior is studied by investigating the temperature-dependent Raman scattering spectra, it is observed that all the Raman peaks show linear stiffening behavior as the temperature decreased from 293 K to 83 K, the temperature coefficients of four prominent Raman peaks suggest the anharmonicity of the lattice in layered NbIrTe4 crystal.