Superior lattice thermal conductance of single layer borophene

TL;DR

This study demonstrates that borophene exhibits an exceptionally high lattice thermal conductance surpassing graphene, due to its structural anisotropy and phonon transmission characteristics, making it promising for thermal management applications.

Contribution

It reveals the superior ballistic thermal conductance of borophene and explains the underlying phonon transmission mechanisms, highlighting its potential for heat dissipation and fundamental phonon transport studies.

Findings

Borophene has higher thermal conductance than graphene.

High-frequency phonons in borophene are one-dimensional.

Borophene's anisotropic structure influences phonon transmission.

Abstract

By way of the nonequilibrium Green's function simulations and first principles calculations, we report that borophene, a single layer of boron atoms that was fabricated recently, possesses an extraordinarily high lattice thermal conductance in the ballistic transport regime, which even exceeds graphene. In addition to the obvious reasons of light mass and strong bonding of boron atoms, the superior thermal conductance is mainly rooted in its strong structural anisotropy and unusual phonon transmission. For low-frequency phonons, the phonon transmission within borophene is nearly isotropic, similar to that of graphene. For high frequency phonons, however, the transmission is one dimensional, that is, all the phonons travel in one direction, giving rise to its ultrahigh thermal conductance. The present study suggests that borophene is promising for applications in efficient heat dissipation and thermal management, and also an ideal material for revealing fundamentals of dimensionality effect on phonon transport in ballistic regime.