Ab-initio study of topological phase tuning in Half-Heusler YPdBi compound

Abstract

The topological phase tuning in Half-Heusler alloys could be hosted from trivial to non-trivial states and vice-versa, either with a small variation in the lattice parameter or by introducing the spin-orbit coupling. First principles simulations of the electronic bulk band structure of the YPdBi compound exhibit the topologically non-trivial semimetal state without and with spin-orbit coupling at equilibrium lattice constant due to the single band-inversion at Γ-point. We observed the topological phase tuning from a non-trivial to a trivial state due to the second band-inversion at Γ-point, after applying the hydrostatic pressure of ∼4 GPa. The semimetallic nature of these compounds is protected by the cubic symmetry of the crystal. Thus, by breaking cubic symmetry of the crystal with the application of uniaxial strain along the c-axis and biaxial strain in the ab-plane, we have noticed the topological phase transition from a non-trivial semimetal state to a topological insulator. The importance of half-Heusler compounds lies in their usage as a promising candidate in nanoelectronic applications.