In many metals, thermal transport is often dominated by electrons, although the lattice contribution can remain appreciable depending on the material. Here, through rigorous first-principles calculations, we uncover a phonon-dominated thermal transport regime in the Weyl semimetals TaAs and TaP. Remarkably, despite its metallic character, TaP exhibits an exceptionally high phonon thermal conductivity (${\kappa }_{\mathrm{ph}}$) of $162\mathrm{W}{\mathrm{m}}^{-1}{\mathrm{K}}^{-1}$ at room temperature, surpassing its electronic counterpart by nearly an order of magnitude. This anomalously high ${\kappa }_{\mathrm{ph}}$ arises from the combined effects of Weyl electronic structure, acoustic phonon bunching, and a large low-frequency–high-frequency phonon gap, which together suppress phonon-electron and three-phonon scattering. The linearly dispersing bands near the Fermi level yield a low electronic density of states, limiting both electrical conductivity and electronic thermal transport in these compounds. By further surveying a broad range of topological semimetals, we show that the prominence of phonon thermal transport is a universal characteristic of this material class. Our work provides deeper insight into thermal transport mechanisms in topological semimetals and broadens the scope for discovering metals with high thermal conductivity.

Close

PrevNext

View figure in article

• Lattice thermal conductivity
• Thermal conductivity
• Weyl semimetal
• Density functional calculations