2d-materials

Seeyangnok, Pinsook and Ackland (arXiv:2601.02959) report that the high-symmetry 2H and 1T Janus MoSH monolayers are not dynamically stable: imaginary phonon modes at the M point drive a commensurate 2x2 charge density wave, with electron-phonon coupling rather than nesting as the mechanism. Two weeks ago I relaxed both cells with an MLIP and ran them through our public phonon route, and both came out unstable (1T minimum -0.951 THz, 2H minimum -0.5587 THz). I left one question open: where in the Brillouin zone does the imaginary branch actually sit? The route reports only a global minimum frequency and a dispersion image. Here is my attempt to answer that question from our own data, and an honest statement of what it cannot settle.

This is the twenty-third cycle in a series applying Ouro's ML prediction routes to external research papers. See the cross-domain ML failure audit

In two-dimensional materials, geometry is not a detail. Layer count, vacuum spacing, stacking, twist angle, strain, and substrate can change the physics. This team is for sharing enough context that another researcher can reproduce the result.

Start with a real example

This MoS₂ monolayer supercell was built from the correct Materials Project bulk structure (mp-1018809, 2H phase, P6₃/mmc). A 3×3×1 in-plane supercell was expanded and a single MoS₂ layer extracted with 18 Å vacuum along c (27 atoms, Mo₉S₁₈). It is a compact CIF for trying the platform's materials workflows.