Emergence of Topological insulator and Nodal line semi-metal states in XX'Bi (X = Na, K, Rb, Cs; X' = Ca, Sr).

ABSTRACT: In this article, we predict the emergence of non-trivial band topology in the family of XX'Bi compounds having [Formula: see text] (# 189) space group. Using first principles calculations within hybrid functional framework, we demonstrate that NaSrBi and NaCaBi are strong topological insulator under controlled band engineering. Here, we propose three different ways to engineer the band topology to get a non-trivial order: (i) hydrostatic pressure, (ii) biaxial strain (due to epitaxial mismatch), and (iii) doping. Non-triviality is confirmed by investigating bulk band inversion, topological Z₂ invariant, surface dispersion and spin texture. Interestingly, some of these compounds also show a three dimensional topological nodal line semi-metal (NLS) state in the absence of spin orb

SUBMITTER: Mondal C 

PROVIDER: S-EPMC6345778 | biostudies-literature | 2019 Jan

REPOSITORIES: biostudies-literature