Strain-engineering the topological type-II Dirac semimetal NiTe$_2$


In this work, the electronic and elastic properties of the type-II Dirac semimetal NiTe2, in equilibrium and under strain, were systematically studied within the scope of density functional theory (DFT) and effective models. We have demonstrated that strain-engineering is an effective route for manipulating its electronic and topological properties. We have shown that compressive and tensile deformations control the Dirac node momentum and their energy relative to the Fermi level. Moreover, it is possible to lower or increase the overlap between the low-energy wave functions and suppress trivial bands, opening the way for superconductivity, Liftshtz transitions, and a hybrid type-I and type-II Dirac semimetallic phase. Furthermore, we provided a minimal effective model for the Dirac cone and derive the mentioned strain effects using lattice regularization, providing an inexpensive way for further theoretical investigations and easy comparison with experiments. We also proposed statically controlling the electronic-structure with the intercalation of alkali-element species into the van der Waals gap, resulting in a similar physical response to the one obtained by strain-engineering.