Effect of Cu Doping on Structure and Physical Properties in the Antiferromagnetic Dirac Semimetal CaMnBi2

Zijing Zhang; Zhongnan Guo; Jiawei Lin; Fan Sun; Xue Han; Gang Wang; Wenxia Yuan

doi:10.1021/acs.inorgchem.1c03410

Effect of Cu Doping on Structure and Physical Properties in the Antiferromagnetic Dirac Semimetal CaMnBi₂

Inorg Chem. 2022 Mar 21;61(11):4592-4597. doi: 10.1021/acs.inorgchem.1c03410. Epub 2022 Mar 10.

Authors

Zijing Zhang¹, Zhongnan Guo¹, Jiawei Lin¹, Fan Sun¹, Xue Han¹, Gang Wang^{2

3

4}, Wenxia Yuan¹

Affiliations

¹ Department of Chemistry, School of Chemistry and Biological Engineering, University of Science and Technology Beijing, Beijing 100083, China.
² Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China.
³ University of Chinese Academy of Sciences, Beijing 100049, China.
⁴ Songshan Lake Materials Laboratory, Dongguan, Guangdong 523808, China.

PMID: 35271274
DOI: 10.1021/acs.inorgchem.1c03410

Abstract

The newly discovered AMnBi₂ (A = Ca, Sr, Ba, Eu, and Yb) materials composed of two-dimensional Bi square nets provide an excellent platform to investigate the effect of magnetism on topological band structures. Effectively tuning the magnetic interaction in AMnBi₂ is of great importance to advance this issue. Here, we describe an effective route to tune the magnetism in Dirac semimetal CaMnBi₂ through Cu doping. Structural analysis on CaMn_1-xCu_xBi₂ single crystals indicates that Cu atoms occupy the Mn sites randomly, with the maximum doping level of 25%. After Cu doping, the Bi square net in charge of the Dirac band is still retained, but the Bi-Bi bond distance is markedly shortened. The antiferromagnetic interaction of CaMnBi₂ is strongly weakened in the Cu-doped crystals, with the transition temperature decreased from 260 to 85 K. On the contrary, the ferromagnetic component that originated from the canted AFM is enhanced, suggesting that the spin canting in this system is tunable. In addition, the magnetoresistance is decreased upon Cu doping, probably due to the disorder in structure. Our work suggests that the CaMn_1-xCu_xBi₂ (0 ≤ x ≤ 0.25) system can offer a suitable playground to address the interplay between magnetism and the topological state.