中国物理B ›› 2021, Vol. 30 ›› Issue (9): 97303-097303.doi: 10.1088/1674-1056/ac0cd7

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High-resolution angle-resolved photoemission study of large magnetoresistance topological semimetal CaAl4

Xu-Chuan Wu(吴徐传), Shen Xu(徐升), Jian-Feng Zhang(张建丰), Huan Ma(马欢), Kai Liu(刘凯), Tian-Long Xia(夏天龙), and Shan-Cai Wang(王善才)   

  1. Department of Physics, Beijing Key Laboratory of Optoelectronic Functional Materials and Micro-nano Devices, Renmin University of China, Beijing 100872, China
  • 收稿日期:2021-04-19 修回日期:2021-06-15 接受日期:2021-06-21 出版日期:2021-08-19 发布日期:2021-09-06
  • 通讯作者: Shan-Cai Wang E-mail:SCW@ruc.edu.cn
  • 基金资助:
    Project supported by the National Natural Science Foundation of China (Grant Nos. 11774421, 12074425, 11874422, 11574391, and 11774424), the National Key Research and Development Program of China (Grant No. 2019YFA0308602), and the Fundamental Research Funds for the Central Universities, China, and the Research Funds of Renmin University of China (Grant Nos. 19XNLG13, 18XNLG14, and 19XNLG18).

High-resolution angle-resolved photoemission study of large magnetoresistance topological semimetal CaAl4

Xu-Chuan Wu(吴徐传), Shen Xu(徐升), Jian-Feng Zhang(张建丰), Huan Ma(马欢), Kai Liu(刘凯), Tian-Long Xia(夏天龙), and Shan-Cai Wang(王善才)   

  1. Department of Physics, Beijing Key Laboratory of Optoelectronic Functional Materials and Micro-nano Devices, Renmin University of China, Beijing 100872, China
  • Received:2021-04-19 Revised:2021-06-15 Accepted:2021-06-21 Online:2021-08-19 Published:2021-09-06
  • Contact: Shan-Cai Wang E-mail:SCW@ruc.edu.cn
  • Supported by:
    Project supported by the National Natural Science Foundation of China (Grant Nos. 11774421, 12074425, 11874422, 11574391, and 11774424), the National Key Research and Development Program of China (Grant No. 2019YFA0308602), and the Fundamental Research Funds for the Central Universities, China, and the Research Funds of Renmin University of China (Grant Nos. 19XNLG13, 18XNLG14, and 19XNLG18).

摘要: Extremely large magnetoresistance (XMR) has been explored in many nonmagnetic topologically nontrivial/trivial semimetals, while it is experimentally ambiguous which mechanism should be responsible in a specific material due to the complex electronic structures. In this paper, the magnetoresistance origin of single crystal CaAl4 with C2/m structure at low temperature is investigated, exhibiting unsaturated magnetoresistance of ~ 3000% at 2.5 K and 14 T as the fingerprints of XMR materials. By the combination of ARPES and the first-principles calculations, we elaborate multiband features and anisotropic Fermi surfaces, which can explain the mismatch of isotropic two-band model. Although the structural phase transition from I4/mmm to C2/m has been recognized, the subtle impact on electronic structure is revealed by our ARPES measurements. Considering that both charge compensation and potential topologically nontrivial band structure exist in CaAl4, our findings report CaAl4 as a new reference material for exploring the XMR phenomena.

关键词: magnetoresistance, angle-resolved photoemission spectroscopy (ARPES), topological semimetal

Abstract: Extremely large magnetoresistance (XMR) has been explored in many nonmagnetic topologically nontrivial/trivial semimetals, while it is experimentally ambiguous which mechanism should be responsible in a specific material due to the complex electronic structures. In this paper, the magnetoresistance origin of single crystal CaAl4 with C2/m structure at low temperature is investigated, exhibiting unsaturated magnetoresistance of ~ 3000% at 2.5 K and 14 T as the fingerprints of XMR materials. By the combination of ARPES and the first-principles calculations, we elaborate multiband features and anisotropic Fermi surfaces, which can explain the mismatch of isotropic two-band model. Although the structural phase transition from I4/mmm to C2/m has been recognized, the subtle impact on electronic structure is revealed by our ARPES measurements. Considering that both charge compensation and potential topologically nontrivial band structure exist in CaAl4, our findings report CaAl4 as a new reference material for exploring the XMR phenomena.

Key words: magnetoresistance, angle-resolved photoemission spectroscopy (ARPES), topological semimetal

中图分类号:  (Magnetoresistance)

  • 73.43.Qt
79.60.-i (Photoemission and photoelectron spectra)