Pressure driven topological phase transition in chalcopyrite ZnGeSb$_2$

TL;DR

This paper reports a first-principles study of chalcopyrite ZnGeSb$_2$, revealing a pressure-induced topological phase transition from non-trivial to trivial, with implications for strain-engineered topological materials.

Contribution

It demonstrates the existence of a strong topologically non-trivial phase in ZnGeSb$_2$ and identifies how hydrostatic pressure induces a topological phase transition.

Findings

ZnGeSb$_2$ exhibits a non-zero $Z_2$ topological invariant.

Dirac cone surface states with spin-momentum locking are present.

Moderate pressure (~7 GPa) causes a transition to a trivial phase.

Abstract

Recently topologically non-trivial phases have been identified in few time-reversal invariant systems that lack of inversion symmetry. Using density functional theory based first-principles calculations, we report a strong topologically non-trivial phase in chalchopyrite ZnGeSb$_2$, which can act as a model system of strained HgTe. The calculations reveal the non-zero topological invariant ($Z_2$), the presence of Dirac cone crossing in the surface spectral functions with spin-momentum locking. We also show that the application of moderate hydrostatic pressure ($\sim$7 GPa) induces topological phase transition from topological non-trivial phase to a topologically trivial phase. A discontinuity in the tetragonal distortion of non-centrosymmetric ZnGeSb$_2$ plays a crucial role in driving this topological phase transition.