Anisotropic intrinsic lattice thermal conductivity of phosphorene from first principles

TL;DR

This study calculates the anisotropic lattice thermal conductivity of phosphorene using first-principles phonon transport equations, revealing directional differences and the impact of phonon modes on thermal properties.

Contribution

The paper provides the first-principles calculation of phosphorene's intrinsic lattice thermal conductivity, highlighting its anisotropy and phonon mode contributions.

Findings

Thermal conductivity at 300K is 30.15 W/mK (zigzag) and 13.65 W/mK (armchair).

Thermal conductivity inversely relates to temperature above Debye temperature.

ZA phonon mode contributes about 5% to the low thermal conductivity.

Abstract

Phosphorene, the single layer counterpart of black phosphorus, is a novel two-dimensional semiconductor with high carrier mobility and a large fundamental direct band gap, which has attracted tremendous interest recently. Its potential applications in nano-electronics and thermoelectrics call for a fundamental study of the phonon transport. Here, we calculate the intrinsic lattice thermal conductivity of phosphorene by solving the phonon Boltzmann transport equation (BTE) based on first-principles calculations. The thermal conductivity of phosphorene at $300\,\mathrm{K}$ is $30.15\,\mathrm{Wm^{-1}K^{-1}}$ (zigzag) and $13.65\,\mathrm{Wm^{-1}K^{-1}}$ (armchair), showing an obvious anisotropy along different directions. The calculated thermal conductivity fits perfectly to the inverse relation with temperature when the temperature is higher than Debye temperature ($\Theta_D = 278.66\,\mathrm{K}$). In comparison to graphene, the minor contribution around $5\%$ of the ZA mode is responsible for the low thermal conductivity of phosphorene. In addition, the representative mean free path (MFP), a critical size for phonon transport, is also obtained.