Strain engineering the topological type-II Dirac semimetal \nNiTe2

Abstract

In this preliminary pre-print, the electronic and elastic properties of the type-II Dirac semimetal NiTe$_2$, in equilibrium and under strain, were systematically studied within the scope of density functional theory. The bulk transition metal dichalcogenide NiTe$_2$ harbor tilted symmetry-protected Dirac cones derived from p-orbital bands in the Fermi level. The projected band-structure and group analysis show that a single orbital-manifold band-inversion is the mechanism behind the presence of the topologically non-trivial states. In this vein, a plethora of distinct strain profiles are shown to be an effective route to manipulate such electronic features. Small compressive and tensile deformations are enough to control the position and energy level of the Dirac-type excitations in the Brillouin zone, tuning the cone position and relative energy to the Fermi level. It is possible to lower or increase the overlap between the wave functions of low-energy valence-bands states and suppress usual bands, abruptly changing its fermiology -- opening the way for electronic phase transitions and a hybrid Dirac semimetal phase. In the next versions, to be released soon, we will provide a minimal effective model for the Dirac cones and derive the mentioned effects of strain using a lattice regularization approach. Additionally, through our investigations of the relationship between electronic and topological phases and its elastic properties, we will propose static-controlling the electronic states by the intercalation of light-metal species into the van der Waals gap, resulting in a similar physical response to the one obtained by dynamical strain-engineering.