The thermal transport characterization of borophene: A molecular dynamics study

Abstract

Over recent years, two-dimensional (2D) boron sheets (borophene) have been reported to have unique properties, but studies on the thermal properties of borophene using molecular dynamics simulation are still few and far between. In this research, phase transition temperature, heat capacity (Cp), thermal expansion coefficients, and the thermal conductivity of borophene were investigated using the molecular dynamics (MD) simulation method via the reactive force field (ReaxFF). The present work is the first to report the exact phase transition temperature for the borophene sheets. The effects of temperature, point defects, and chirality angle on the thermal conductivity of these sheets were further studied. In addition, an approximate structure parameter on the relaxed system was obtained. Although a theoretical study predicted the structure parameter of borophene, it can be inferred that the ReaxFF was incapable of accurately predicting the borophene lattice parameters. Our simulation results were well in line with the available values reported in other studies where the thermal conductivity of borophene decreased with the increase in temperature. Moreover, the chirality angle effect showed that the thermal conductivity of borophene was anisotropic, and the thermal conductivity in the armchair direction was noticeably larger than that in the zigzag direction. Furthermore, it was confirmed that the thermal conductivity was extremely dependent on the vacancy defects. Understanding the thermal properties of borophene may be crucial for expanding its application in novel nanosystems.