Lattice thermal conductivity of SiC in biphenylene network: a first-principles study

The first-principles calculations based on density functional theory (DFT) were performed using the Vienna Ab initio Simulation Package (VASP) . Structural optimization was carried out with the generalized gradient approximation (GGA) in the Perdew-Burke-Ernzerhof (PBE) formulation for the exchange-correlation functional . The plane-wave cutoff energy for structure optimization was set to 500 eV. During structural relaxation, a k-point grid of 6×4×1 was adopted for Brillouin zone integration.Phonon dispersion spectra were calculated using the Phonopy package, while lattice thermal conductivity was calculated with the ShengBTE code . Both second-order and third-order interatomic force constants (IFCs) were determined through the finite displacement method. The second-order IFCs within the harmonic approximation were calculated using a 5 × 3 × 1 supercell with a 1 ×1× 1 k-point mesh. For the third-order IFCs beyond the harmonic approximation , calculations were performed using a 5×3×1 supercell configuration.