The high pressure structural and electronic evolution of bulk MoS2, an important transition metal layered dichalchogenide, is currently under active investigation. Recent theoretical and experimental work predicted and verified a 2Hc→ 2Ha layer sliding structural transition at 20 GPa and a band overlap semiconductor-semimetal transition in the same pressure range. The 2Ha structure is known to persist up to pressure of 81 GPa but properties at higher pressures remain experimentally unknown. Here we predict, with a reliable first-principles evolutionary search, that major structural transformations should take place in equilibrium at higher pressures near 130-140 GPa. The main motif is a decomposition into MoS + S, also heralded in a small bimolecular cell by the appearance of a metastable non-layered metallic MoS2 structure with space group \textit{P4/mmm}. Unlike semimetallic 2Ha-MoS2, both this phase and sulphur in the fully phase separated system are fully metallic and superconducting with higher critical temperatures than alkali-intercalated MoS2.
@article{arxiv.1412.3966,
title = {High Pressure Structure and Decomposition of MoS$_{2}$},
author = {Oto Kohulák and Roman Martoňák and Erio Tosatti},
journal= {arXiv preprint arXiv:1412.3966},
year = {2015}
}