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 NiTe2, which hosts type-II Dirac points close to the Fermi level and topological surface states originating from band inversions along the Γ-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 NiTe2, in agreement with theoretical predictions. Our study suggests the possibility of tuning NiTe2's topological surface states with external uniaxial strain, leading to further studies on diverse strain conditions and spintronic applications.