Electron-phonon scattering in Janus 1T-SnSSe monolayer with an asymmetric structure

Abstract

The thermalization of hot carriers is a critical factor in developing novel functional materials, with the electron–phonon scattering rate recognized as the primary mechanism driving this process. In this study, the electron–phonon scattering rate in Janus 1T-SnSSe monolayer near the Fermi level was calculated using density functional theory (DFT) combined with the Wannier function. The results indicated a strong dependence of the electron–phonon scattering rate on electron energy at 300 K. Among the various lattice vibration modes, the out-of-plane transverse optical phonon branch had the most significant influence on the electron–phonon scattering rate, resulting in rapid thermalization of hot carriers, with a timescale of 238 fs. This rapid thermalization was attributed to the degenerate splitting of the phonon frequency band caused by the lack of mirror symmetry at the Sn atom’s structural center. The absence of mirror symmetry led to this phonon band splitting, which accelerated the thermalization of hot carriers. Additionally, the mean free paths (MFPs) in the zigzag and armchair directions exhibited notable differences, leading to highly anisotropic transport properties in Janus 1T-SnSSe monolayer. It was concluded that the collection of hot carriers is most efficient in the zigzag direction.