Infrared Optical Conductivity of Bulk Bi2Te2Se
Infrared Optical Conductivity of Bulk Bi2Te2Se
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DOI：
10.3390/cryst10070553
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发表时间：
2020-06
期刊：
影响因子：
2.7
通讯作者：
E. Zhukova;Hongbin Zhang;V. Martovitskiy;Yu. G. Selivanov;B. Gorshunov;M. Dressel
中科院分区：
文献类型：
--
作者：
E. Zhukova;Hongbin Zhang;V. Martovitskiy;Yu. G. Selivanov;B. Gorshunov;M. Dressel
中红外和近红外测量表明，三维拓扑绝缘体，Bi 2 Te 2Se，的光学电导率主要由体载流子，并显示在0.5至0.8 eV的线性频率增加。这种线性可能被解释为三维（体）狄拉克带的特征;然而，带结构计算表明，复杂色散的带之间的跃迁反而有助于这些频率下的带间光学电导率，因此，观察到的线性是偶然的。这些结果警告对不同狄拉克材料的光导测量的过度简化的解释。
Mid- and near-infrared measurements reveal that the optical conductivity of the three-dimensional topological insulator, Bi2Te2Se, is dominated by bulk carriers and shows a linear-in-frequency increase at 0.5 to 0.8 eV. This linearity might be interpreted as a signature of three-dimensional (bulk) Dirac bands; however, band-structure calculations show that transitions between bands with complex dispersion contribute instead to the inter-band optical conductivity at these frequencies and, hence, the observed linearity is accidental. These results warn against the oversimplified interpretations of optical-conductivity measurements in different Dirac materials.