Effect of deformation on the electronic structure and topological properties of the AIIMg2Bi2 (AII = Mg,Ca,Sr,Ba) compounds

The electronic structure and topological properties of the AIIMg2Bi2 (AII = Mg,Ca,Sr,Ba) compounds are theoretically studied with the use of exact exchange. It is found that the MgBi compound in the equilibrium state is a semimetal, whereas three other compounds are semiconductors with a direct fundamental band gap. It is predicted that the uniaxial deformation of three-component compounds results in transitions to topologically nontrivial phases: topological insulator and topological and Dirac semimetals. Owing to such a rich variety of topologically nontrivial phases, these compounds may be of interest for further theoretical and experimental studies.This work was supported by Tomsk State University (project no. 8.1.05.2015, program Mendeleev Scientific Foundation), by St. Petersburg State University (project no. 15.61.202.2015), by the Russian Foundation for Basic Research (project no. 15-02-02717-а), and by the Ministry of Education and Science of the Russian Federation (project no. 3.9003.2017/P220).Peer Reviewe