Topological Phase Transition in Non-centrosymmetric LiCaBi Compound: A First-principles Study

The topological insulators (TIs) exhibiting robust edge/surface states are of great importance owing to their dissipation less spin transport. The non-centrosymmetric compounds exhibiting P6̅2m space group with bulk inversion asymmetry are scarcely explored for different topological phases. The present study employs density functional theory based on first-principles to investigate the topological insulating phase in the LiCaBi compound. We applied biaxial strain along [110] direction and hydrostatic pressure through lattice expansion to realize the topological phase transition (TPT). To rule out the overestimation of band inversion using generalized gradient approximation (GGA), we have also used a more accurate hybrid functional (HSE06). The calculated Z2 topological invariants, the evolution of Wannier charge centers, and Dirac-cone like surface states indicate the strong topological insulating nature of the LiCaBi compound, suggesting its potential applications in quantum computing, spintronics, nanoelectronics, etc. Our calculation also confirms the dynamical, mechanical, and thermal stability of the LiCaBi compound. Recently synthesized group I–II–V-based materials indicate the likelihood of LiCaBi synthesis. Our findings motivate further exploration of the topological phases in materials with the P6̅2m space group.