Anisotropic Raman spectrum and transport properties of AuTe2Br flakes
Anisotropic Raman spectrum and transport properties of AuTe2Br flakes
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AuTe2Br 薄片的各向异性拉曼光谱和传输特性
DOI：
10.1088/1361-648x/ab5cb4
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发表时间：
2020
期刊：
影响因子：
--
通讯作者：
Chen Jian-Hao
中科院分区：
文献类型：
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作者：
Cao Shimin;Ma Wenlong;Zhai Gan;Xie Zhijian;Gao Xueshi;Zhao Yan;Ma Xiumei;Tong Lianming;Jia Shuang;Chen Jian-Hao
利用拉曼光谱和磁输运测量研究了拓扑半金属aute2br薄片。aute2br（块状和薄片状）的角分辨偏振拉曼光谱表现出较强的各向异性。结合高分辨率透射电子显微镜（TEM），建立了一种无损测定aute2br薄片晶体取向的方法。在高温（50 K）下，aute2br薄片的磁电阻表现出典型的抛物线状行为，可以用双流体模型很好地拟合。然而，在低温（T≤30 K）下，薄片（< 17 nm）的MR明显偏离了双流体模型和Kohler规则，表明在30 K以下出现了一种新的散射类型。讨论了几种可能的散射机制，并与实验数据进行了比较。此外，这些金属晶体的电导率也被发现是高度各向异性的，沿a轴的空穴迁移率大约是沿c轴的5倍。
Topological semimetal (TSM) AuTe 2 Br thin flakes have been studied by Raman spectroscopy and magneto-transport measurement. The angle-resolved polarized Raman spectrum of AuTe 2 Br (bulk and thin flake) shows strong anisotropy. Together with high resolution transmission electron microscopy (TEM), we establish a non-destructive method to determine the crystallographic orientation of AuTe 2 Br flakes. At high temperature (T> 50 K), the magneto-resistance (MR) of AuTe 2 Br thin flakes shows typical parabolic-like behavior, which can be well fitted by the two-fluid model. However, at low temperature (T⩽ 30 K), the MR of thin flakes (< 17 nm) clearly deviates from the two-fluid model as well as from the Kohler's rule, suggesting a new type of scattering emerging below 30 K. Several possible scattering mechanisms are discussed and the respective corrections to MR are compared with our experimental data. In addition, the conductivity of these metallic crystals is also found to be highly anisotropic, with the hole mobility along the a axis about five times higher than that along the c axis.