Optical study of magnetic topological insulator MnBi_(4)Te_7  

作　　者：廖知裕 沈冰 邱祥冈 许兵 Zhi-Yu Liao;Bing Shen;Xiang-Gang Qiu;Bing Xu(Beijing National Laboratory for Condensed Matter Physics,Institute of Physics,Chinese Academy of Sciences,Beijing 100190,China;School of Physical Sciences,University of Chinese Academy of Sciences,Beijing 100049,China;State Key Laboratory of Optoelectronic Materials and Technologies,School of Physics,Sun Yat-Sen University,Guangzhou 510275,China;Songshan Lake Materials Laboratory,Dongguan 523808,China)

机构地区：[1]Beijing National Laboratory for Condensed Matter Physics,Institute of Physics,Chinese Academy of Sciences,Beijing 100190,China [2]School of Physical Sciences,University of Chinese Academy of Sciences,Beijing 100049,China [3]State Key Laboratory of Optoelectronic Materials and Technologies,School of Physics,Sun Yat-Sen University,Guangzhou 510275,China [4]Songshan Lake Materials Laboratory,Dongguan 523808,China

出　　处：《Chinese Physics B》2024年第1期231-235,共5页中国物理B（英文版）

基　　金：Project supported by the the National Natural Science Foundation of China (Grant No.12274442);the National Key R&D Program of China (Grant No.2022YFA1403901)。

摘　　要：We present an infrared spectroscopy study of the magnetic topological insulator MnBi_(4)Te_7 with antiferromagnetic(AFM) order below the Neel temperature TN= 13 K. Our investigation reveals that the low-frequency optical conductivity consists of two Drude peaks, indicating a response of free carriers involving multiple bands. Interestingly, the narrow Drude peak grows strongly as the temperature decreases, while the broad Drude peak remains relatively unchanged. The onset of interband transitions starts around 2000 cm^(-1), followed by two prominent absorption peaks around 10000 cm^(-1) and 20000 cm^(-1). Upon cooling, there is a notable transfer of spectral weight from the interband transitions to the Drude response. Below TN, the AFM transition gives rise to small anomalies of the charge response due to a band reconstruction.These findings provide valuable insights into the interplay between magnetism and the electronic properties in MnBi_(4)Te_7.

关 键 词：infrared spectroscopy magnetic topological insulator Drude model band reconstruction 

分 类 号：O469[理学—凝聚态物理]