First-principles study of the crystal structure, electronic structure, and transport properties of NiTe$_2$ under pressure

TL;DR

This study uses first-principles calculations to explore how pressure affects NiTe₂'s structure, electronic properties, and transport behavior, clarifying experimental controversies about its superconductivity and Hall effect under pressure.

Contribution

It predicts pressure-induced structural phase transitions and topological properties in NiTe₂, and explains the pressure and doping sensitivity of its Hall resistance.

Findings

NiTe₂ transitions from P-3m1 to Pa-3 phase around 10 GPa

Both phases exhibit nontrivial topological properties

Superconducting transition temperature approaches 0 K under pressure

Abstract

Recent experiments showed the distinct observations on the transition metal ditelluride 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 NiTe$_2$ with structure searching and optimization. Our calculations show that the pressure can transform NiTe$_2$ from a layered P-3m1 phase to a cubic Pa-3 phase at $\sim$10 GPa. Meanwhile, both the P-3m1 and Pa-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-3 phase is sensitive to the pressure and the charge doping, in contrast to the case of the P-3m1 phase. Our theoretical predictions on the compressed NiTe$_2$ wait for careful experimental examinations.