FIRST-PRINCIPLES STUDY OF THE LATTICE THERMAL CONDUCTIVITY OF MoSi2P4 AND WSi2P4 MONOLAYERS

Recently, the 2D van der Waals (vdW) layered MA(2)Z(4) series has attracted a lot of attention. Among these 2D materials, MoSi2P4 and WSi2P4 monolayers each demonstrate strong environmental stability, a moderate band gap, and considerable carrier mobility. The lattice thermal transport properties in MoSi2P4 and WSi2P4 monolayer structures have been investigated using first-principles calculations. Due to the gap present in the phonon energy band structure of the WSi2P4 monolayer within the middle frequency range, the specific heat capacity, phonon group velocity, and phonon relaxation time of the WSi2P4 monolayer structure are smaller than those of the MoSi2P4 monolayer structure. This makes the lattice thermal conductivity of the WSi2P4 monolayer lower than that of the MoSi2P4 monolayer. The MoSi2P4 structure has a lattice thermal conductivity of 28 W/mK at 300 K. The WSi2P4 structure has a lattice thermal conductivity of 14.5 W/mK in the x -direction and 15 W/mK in the y-direction. The results suggest that the MoSi2P4 and WSi2P4 monolayers can be potentially used as nanoelectronics devices for thermal transport applications.