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

• Investigated electron-phonon scattering effects on transport properties in asymmetric Janus 1T-SnSSe monolayer. • Examined the influence of electron-phonon scattering on the thermalization rate of hot carriers near the bandgap. • Analyzed the impact of phonon band splitting, induced by the absence of mirror symmetry, on the thermal acceleration of hot carriers. • Explored hot carrier extraction along different directions in high-symmetry points. 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.