Discovery of a Robust Non-Janus Hybrid MoSH Monolayer as a Two-Gap Superconductor via High-Throughput Computational Screening

Abstract

The atomic-scale determination of hydrogen positions in MoSH monolayers remains experimentally challenging, and existing studies are confined to Janus-type configurations. Here, we combine high-throughput structural screening with first-principles calculations to predict a novel non-Janus Hybrid 1T${}^{{}^{\prime }}$-MoSH monolayer, which energetically surpasses all previously reported MoSH phases with a binding energy of -3.02 eV. This structure emerges as a hybrid of MoS${}_2$ and MoH${}_2$, featuring alternating S and H atoms on both sides of the Mo layer. Comprehensive stability analyses confirm its robustness in energy, mechanics, dynamics, and thermodynamics (stable up to 1600 K). Remarkably, anisotropic Migdal-Eliashberg theory predicts Hybrid 1T${}^{{}^{\prime }}$-MoSH as a two-gap superconductor with a critical temperature T${}_c$ of 16.34 K, driven by strong electron-phonon coupling ($\hat{I}»$$=$1.39). Substituting Mo with Hf, Ta, or Ti drastically suppresses T${}_c$ $\sim$ (0.53-2.42 K), highlighting Mo${}^{{}^{\prime }}$s unique role in enhancing superconductivity. Our work not only expands the family of 2D transition metal chalcogenides but also proposes a promising candidate for quantum technologies, bridging theoretical design to functional material discovery.