Issue 42, 2020

High thermal conductivity driven by the unusual phonon relaxation time platform in 2D monolayer boron arsenide

Abstract

The cubic boron arsenide (BAs) crystal has received extensive research attention because of its ultra-high thermal conductivity comparable to that of diamond. In this work, we performed a comprehensive study on the diffusive thermal properties of its two-dimensional (2D) counterpart, the monolayer honeycomb BAs (h-BAs), through solving the phonon Boltzmann transport equation combined with first-principles calculation. We found that unlike the pronounced contribution from out-of-plane acoustic phonons (ZA) in graphene, the high thermal conductivity (181 W m−1 K−1 at 300 K) of h-BAs is mainly contributed by in-plane phonon modes, instead of the ZA mode. This result is explained by the unique frequency-independent ‘platform’ region in the relaxation time of in-plane phonons. Moreover, we conducted a comparative study of thermal conductivity between 2D h-BAs and h-GaN, because both of them have a similar mass density. The thermal conductivity of h-BAs is one order of magnitude higher than that of h-GaN (16 W m−1 K−1), which is governed by the different phonon scattering process attributed to the opposite wavevector dependence in out-of-plane optical phonons. Our findings provide new insight into the physics of heat conduction in 2D materials, and demonstrate h-BAs to be a new thermally conductive 2D semiconductor.

Graphical abstract: High thermal conductivity driven by the unusual phonon relaxation time platform in 2D monolayer boron arsenide

Article information

Article type
Paper
Submitted
29 May 2020
Accepted
25 Jun 2020
First published
02 Jul 2020
This article is Open Access
Creative Commons BY license

RSC Adv., 2020,10, 25305-25310

High thermal conductivity driven by the unusual phonon relaxation time platform in 2D monolayer boron arsenide

Y. Hu, D. Li, Y. Yin, S. Li, H. Zhou and G. Zhang, RSC Adv., 2020, 10, 25305 DOI: 10.1039/D0RA04737F

This article is licensed under a Creative Commons Attribution 3.0 Unported Licence. You can use material from this article in other publications without requesting further permissions from the RSC, provided that the correct acknowledgement is given.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements