First-principles study of the crystal structure, electronic structure, and transport properties of NiTe 2 under pressure

Recent experiments showed the distinct observations on the transition-metal ditelluride ${\mathrm{NiTe}}_{2}$ under pressure: one reported a superconducting phase transition at 12 GPa, whereas another observed a sign reversal of Hall resistivity at 16 GPa without the appearance of superconductivity. To clarify the controversial experimental phenomena, we have carried out first-principles electronic structure calculations on the compressed ${\mathrm{NiTe}}_{2}$ with structure searching and optimization. Our calculations show that the pressure can transform ${\mathrm{NiTe}}_{2}$ from a layered $P\text{\ensuremath{-}}3m1$ phase to a cubic $Pa\text{\ensuremath{-}}3$ phase at $\ensuremath{\sim}10\phantom{\rule{0.28em}{0ex}}\mathrm{GPa}$. Meanwhile, both $P\text{\ensuremath{-}}3m1$ and $Pa\text{\ensuremath{-}}3$ phases possess nontrivial topological properties. The calculated superconducting ${T}_{c}$'s for these two phases based on the electron-phonon coupling theory both approach 0 K. Further magnetic transport calculations reveal that the sign of Hall resistance for the $Pa\text{\ensuremath{-}}3$ phase is sensitive to the pressure and the charge doping, in contrast to the case of the $P\text{\ensuremath{-}}3m1$ phase. Our theoretical predictions on the compressed ${\mathrm{NiTe}}_{2}$ wait for careful experimental examinations.