Topological Type-II Nodal Line Semimetal and Dirac Semimetal State in Stable Kagome Compound Mg3Bi2

Xiaoming Zhang; Lei Jin; Xuefang Dai; Guodong Liu

doi:10.1021/acs.jpclett.7b02129

Topological Type-II Nodal Line Semimetal and Dirac Semimetal State in Stable Kagome Compound Mg₃Bi₂

J Phys Chem Lett. 2017 Oct 5;8(19):4814-4819. doi: 10.1021/acs.jpclett.7b02129. Epub 2017 Sep 21.

Authors

Xiaoming Zhang¹, Lei Jin¹, Xuefang Dai¹, Guodong Liu¹

Affiliation

¹ School of Materials Science and Engineering, Hebei University of Technology , Tianjin 300130, China.

PMID: 28927265
DOI: 10.1021/acs.jpclett.7b02129

Abstract

Topological type-II nodal line semimetal (NLS) was proposed quite recently and exhibits distinct properties compared with conventional type-I NLS. To date, no ambient-condition stable candidate material has been reported. Here we propose that a stable Kagome compound Mg₃Bi₂ can host a type-II nodal line state with the protection of time reversal and spatial inversion symmetries. Similar to type-I NLSs, the type-II nodal line in Mg₃Bi₂ is characterized by the drumhead surface states, which has not been observed in the previous type-II NLSs. The nodal line in Mg₃Bi₂ can open a minor gap, and a pair of 3D Dirac points occurs when SOC is included. The SOC-induced gap around the nodal line is quite small, and the formation of 3D Dirac points is independent of the nodal line. Therefore, the Mg₃Bi₂ compound is expected to be a good candidate to investigate the exotic properties of both type-II NLS and 3D Dirac semimetal states.