Discovery of a robust non-Janus hybrid MoSH monolayer as a two-gap superconductor via high-throughput computational screening

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'-MoSH monolayer, which energetically surpasses all previously reported MoSH phases with a binding energy of \ensuremath{-}3.02 eV. This structure emerges as a hybrid of ${\mathrm{MoS}}_{2}$ and ${\mathrm{MoH}}_{2}$, 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'-MoSH as a two-gap superconductor with a critical temperature ${T}_{\mathrm{c}}$ of 17.5 K, driven by strong electron-phonon coupling ($\ensuremath{\lambda}=1.33$). Substituting Mo with Hf, Ti, or Ta drastically suppresses ${T}_{\mathrm{c}}\ensuremath{\sim}(0.53\ensuremath{-}2.42\phantom{\rule{0.16em}{0ex}}\mathrm{K})$, highlighting Mo'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.