Unveiling strain-responsive topological landscapes in the NiTe2 Dirac semimetal

We report strain induced modification of the topological surface band structure of layered transition metal dichalcogenide ${\mathrm{NiTe}}_{2}$, which hosts type-II Dirac points close to the Fermi level and topological surface states originating from band inversions along the $\mathrm{\ensuremath{\Gamma}}\text{\ensuremath{-}}A$ direction of the Brillouin zone. By means of first-principles density functional theory calculations, we predict the evolution of the surface states, analyzing their dispersion and spin texture, eventually showing a relevant modulation of their filling as a function of the uniaxial in-plane strain conditions. Synchrotron-based angle-resolved photoemission experiments, using an experimental setup to induce strain in two-dimensional layered materials, demonstrate a clear variation of the spin-polarized topological surface band structure of ${\mathrm{NiTe}}_{2}$, in agreement with theoretical predictions. Our study suggests the possibility of tuning ${\mathrm{NiTe}}_{2}$'s topological surface states with external uniaxial strain, leading to further studies on diverse strain conditions and spintronic applications.