Lattice Thermal Conductivity of Sun-Graphyne from Reverse Nonequilibrium Molecular Dynamics Simulations

Abstract: The thermal conductivity of two-dimensional (2D) materials is critical in determining their suitability for several applications, from electronics to thermal management. In this study, we have used Molecular Dynamics (MD) simulations to investigate the thermal conductivity and phononic properties of 8-16-4(Sun)-Graphyne, a recently proposed 2D carbon allotrope. The thermal conductivity was estimated using reverse non-equilibrium MD simulations following the Muuller-Plathe approach, revealing a strong dependence on system size. Phonon dispersion calculations confirm the stability of Sun-GY while also showing a significant decrease in thermal conductivity compared to graphene. This decrease is attributed to acetylenic bonds, which enhance phonon scattering. Spectral analysis further revealed that Sun-GY exhibits lower phonon group velocities and increased phonon scattering, mainly due to interactions between acoustic and optical modes. Sun-GY presents an intrinsic thermal conductivity of approximately 24.6 W/mK, much lower than graphene, making it a promising candidate for applications that require materials with reduced thermal transport properties.