Phonon transport of three-fold degeneracy topological semimetal MoP

TL;DR

This study investigates phonon transport in the topological semimetal MoP, revealing highly anisotropic thermal conductivity and minimal isotope effects, which are crucial for thermal management in MoP-based nano-electronics.

Contribution

It provides the first detailed calculation of phonon thermal transport in MoP, highlighting anisotropic conductivity and the influence of isotope and size effects, advancing understanding of thermal properties in topological semimetals.

Findings

Room-temperature thermal conductivity is 18.41 and 34.71 W/m·K along different directions.

Isotope scattering has little effect on thermal conductivity.

Phonons contribute minimally to thermal transport when mean free path exceeds 0.15 μm.

Abstract

Recently, three-component new fermions in topological semimetal MoP are experimentally observed, which may have potential applications like topological qubits, low-power electronics and spintronics. These are closely related to thermal transport properties of MoP. In this work, the phonon transport of MoP is investigated by solving the linearized phonon Boltzmann equation within the single-mode relaxation time approximation (RTA). The calculated room-temperature lattice thermal conductivity is 18.41 $\mathrm{W m^{-1} K^{-1}}$ and 34.71 $\mathrm{W m^{-1} K^{-1}}$ along the in- and cross-plane directions, exhibiting very strong anisotropy. The isotope and size effects on the lattice thermal conductivity are also considered. It is found that isotope scattering produces little effect, and phonon has little contribution to the lattice thermal conductivity, when phonon mean free path(MFP) is larger than 0.15 $\mathrm{\mu m}$ at 300 K. It is noted that average room-temperature lattice thermal conductivity of MoP is lower than that of representative Weyl semimetal TaAs, which is due to smaller group velocities and larger Gr$\mathrm{\ddot{u}}$neisen parameters. Our works provide valuable informations for the thermal management of MoP-based nano-electronics devices, and motivate further experimental works to study thermal transport of MoP.