Ab initio investigation of single-layer high thermal conductivity boron compounds

Abstract

The discovery and design of materials with large thermal conductivities (κ L ) is critical to address future heat management challenges, particularly as devices shrink to the nanoscale. This requires developing novel physical insights into the microscropic interactions and behaviors of lattice vibrations. Here, we use ab initio phonon Boltzmann transport calculations to derive fundamental understanding of lattice thermal transport in two-dimensional (2D) monolayer hexagonal boron-based compounds, h-BX (X = N, P, As, Sb). Monolayer h-BAs, in particular, possesses structural and dispersion features similar to bulk cubic BAs and 2D graphene, which govern their ultrahigh room temperature κ L (1300 W/m K and 2000-4000 W/m K, respectively), yet here combine to give significantly lower κ L for monolayer h-BAs (400 W/m K at room temperature). This work explores this discrepancy, and thermal transport in the monolayer h-BX systems in general, via comparison of the microscopic mechanisms that govern phonon transport. In particular, we present calculations of phonon dispersions, velocities, scattering phase space and rates, and κ L of h-BX monolayers as a function of temperature, size, defects, and other fundamental parameters. From these calculations, we make predictions of the thermal conductivities of h-BX monolayers, and more generally develop deeper fundamental understanding of phonon thermal transport in 2D and bulk materials.

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

“…The calculated lattice constant of 3.39 A is coincident well with previous works. 18,24,25,33 (1.34e). 37 On the other side, the charge transfer in the z direction is only 0.051e, much smaller than InSe (0.27e) and MoS 2 (0.14e), because its ideal planar geometry.…”

“…Compared with other 2D III-V honeycomb lattice, what is the unique phonon scheme in h-BAs? Although preliminary literatures reported high thermal conductivity of h-BAs, 32,33 compared with the extensive studies of thermal conductivity of graphene and h-BN, there are still many open questions. Obviously, a better knowledge of thermal conductivity of h-BAs is highly important not only for fundamental physics of low-dimensional thermal transport, but also for technological applications such as thermal management of nanoscale integrated devices.…”

Thermoelectric transports in pristine and functionalized boron phosphide monolayers

“…The experimental realization of crystalline BP thin film has further suggested its possibility in practical use. Unfortunately, the thermal conductivity of 220–323 W/mK in BP monolayer 31 , 32 is rather high compared with other two-dimensional thermoelectric materials. To address this problem, the idea of using van der Waals interaction to reduce the lattice thermal conductivity has been applied.…”

Emerging interface materials for electronics thermal management: experiments, modeling, and new opportunities

“…Such a DFT-based approach has been applied for electronic calculations for decades but for phonons more recently. [47][48][49][50] Molecular dynamics. In MD simulations, 51 the dynamical trajectories, velocities and forces of atoms are simulated following Newton's equation of motion.…”