Our third paper of 2017 “Anomalous strain effect on the thermal conductivity of borophene: a reactive molecular dynamics study” has just been accepted for publication in Physica E: Low-dimensional systems and nanostructures.
Borophene, an atomically thin, corrugated, crystalline two-dimensional boron sheet, is one of the latest additions to the 2D materials family. In this work we investigate mechanical properties and lattice thermal conductivity of borophene using reactive molecular dynamics simulations. We found an anisotropy in 2D elastic moduli along perpendicular directions, dubbed zigzag and armchair directions, in analogy with the direction in graphene. We attribute the anisotropy to the buckling of the borophene structure along the zigzag direction. We performed non-equilibrium molecular dynamics simulations to calculate the lattice thermal conductivity, and found an anisotropy along the in-plane directions, also in accordance with our estimate for the effective phonon mean free paths. In this case, the anisotropy is attributed to differences in the density of states of low-frequency phonons, with lower group velocities and possibly shorten phonon lifetimes along the zigzag direction. Finally, we found that when borophene is strained along the armchair direction there is a significant increase in thermal conductivity along that direction. Meanwhile, when the sample is strained along the zigzag direction there is a much smaller increase in thermal conductivity along that direction. Our predictions are in agreement with recent first principles results, at a fraction of the computational cost.
The manuscript is a product of our ongoing collaboration with Dr. Bohayra Mortazavi and Prof. Timon Rabczuk at Bauhaus-Universität Weimar. The thermal transport simulations were performed at the High Performance Computing Center (NPAD) at UFRN.
The paper is available here. Free access here (until 11/Aug/2017). A preprint version is available here.