Phonon transport in 1T and 1 H − NiTe 2 under the dominance of anharmonicity and electron-phonon coupling

Recently, NiTe₂ has emerged as a representative metallic transition-metal dichalcogenide (TMD), owing to its tunable electronic transport, high current-carrying capability, and experimental accessibility. However, its phonon transport behavior remains unclear. Here, we employ first-principles calculations to investigate the lattice thermal conductivity (kₚ) of both 1T and 1H phases for NiTe₂. Our results show that in 1T phase, four-phonon (4ph) processes reduce kₚ by up to 58.2%, lowering kₚ from 3.79/4.69 to 1.70/1.96 W m^-1 K^-1 along the armchair/zigzag directions. Electron-phonon interaction (EPI) leads to an additional maximum 29.5% suppression, reducing kₚ to 0.58 W m^-1 K^-1 at a carrier concentration of 1 ×{} 10¹⁴ cm^-2 in n-type 1T-NiTe₂. In contrast, the 1H phase exhibits a more moderate decrease, with kₚ reduced from 3.61 to 2.44 W m^-1 K^-1 by 4ph scattering. The most distinct EPI effect in 1H-NiTe₂ occurs in the intrinsic state, further reducing kₚ to 1.57 W m^-1 K^-1. The more pronounced suppression in kₚ in 1T-NiTe₂ originates from the larger phonon band gap and higher electronic density of states compared with 1H-NiTe₂. Our results suggest viable routes to tune phonon transport in TMDs via phase control and carrier engineering.