Strain-engineering of Topological Type-II Dirac Semimetal NiTe₂

The electronic, elastic and topological properties of the equilibrium and strained type-II Dirac semimetal NiTe₂ were studied within the scope of density functional theory. This bulk transition metal dichalcogenide harbor a tilted symmetry-protected Dirac cone from p-orbital bands in the vicinity of the Fermi level. The projected electronic structure and group analysis suggest that single orbital-manifold band inversion can be assigned as the mechanism behind the present topologically non-trivial states. Also, several applied strain modes are shown to be an effective route to tuning this bulk electronic trends. For instance, a small uniaxial strain along z-direction is enough to approach Dirac fermions into the Fermi energy and supress another usual non-relativistic bands from the Fermi surface. Through our investigations, we propose a static-control of the electronic states by the intercalation of light-metal monovalent species into the van der Waals gap. We also present a low-energy effective model and discuss effects of external fields and low-dimensionality.