Anisotropic Thermal Conductivity in Two-Dimensional B8Si4: A First-Principles Study

Abstract We report a comprehensive study on the thermal conductivity of two-dimensional (2D) B8Si4 using first-principles calculations and the Peierls–Boltzmann transport equation. Thermal conductivity calculations reveal significant anisotropy, with values of 147.0 Wm⁻¹K⁻¹ along the x direction and 111.0 Wm⁻¹K⁻¹ along the y direction at 300 K. These values are comparable to silicon, highlighting the efficient thermal dissipation capabilities of 2D B8Si4. The major contributions to thermal conductivity come from in-plane acoustic modes (LA and TA), whereas the contribution from out-of-plane acoustic (ZA) modes is relatively minor due to their shorter lifetimes and lower group velocities. The findings suggest that 2D B8Si4 is a promising material for applications in nanoelectronics and thermal management, offering substantial thermal conductivity and anisotropic heat dissipation properties. This study provides a foundational understanding of the thermal properties of 2D B8Si4, paving the way for future research into its potential technological applications.