Strong Lattice\nAnharmonicity and Superconductivity\nin Janus 1T-Phase MoSH

An accurate description of the vibrations of atoms is\nessential\nfor studying the stability and superconductivity, especially for materials\nwith strong lattice anharmonicity. The recently synthesized Janus\nMoSH has sparked extensive research interest due to its unique physical\nstructure. However, under the harmonic approximation, the 1T phase\nexhibits a charge density wave state, which is considered to be lattice\ndynamically unstable. In this study, we used the stochastic self-consistent\nharmonic approximation (SSCHA) to investigate the anharmonic lattice\ndynamics of 1T-MoSH. The results indicate that the 1T phase is stable,\nrevealing the crucial role of lattice anharmonicity in destroying\nthe charge density wave (CDW) state. Furthermore, the <i>ab initio</i> molecular dynamics (AIMD) simulations show the superior thermal\nstability of the 1T phase compared to that of the 2H phase. Through\nthe study of electronic structure and electron–phonon interaction\nmechanisms, the electron–phonon coupling (EPC) constant of\n1T-MoSH is determined to be 1.68, with the main source of EPC being\nthe interaction between electrons on the Mo atom’s out-of-plane dz2 orbital and the vibration of the Mo atom.\nBy solving the anisotropic Migdal–Eliashberg equations, the\nsuperconducting transition temperature <i>T</i><sub>c</sub> of 24.43K is obtained, revealing that 1T-MoSH is a phonon-mediated\nsuperconductor with a single-gap. Our study lays the foundation for\nfurther investigation of the lattice vibration-related properties\nof MoSH.