High Pressure Structure and Decomposition of MoS${}_2$

Abstract

The high pressure structural and electronic evolution of bulk MoS${}_2$, an important transition metal layered dichalchogenide, is currently under active investigation. Recent theoretical and experimental work predicted and verified a 2H${}_c\to$ 2H${}_a$ layer sliding structural transition at 20 GPa and a band overlap semiconductor-semimetal transition in the same pressure range. The 2H${}_a$ 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 MoS${}_2$ structure with space group \textit{P4/mmm}. Unlike semimetallic 2H${}_a$-MoS${}_2$, both this phase and sulphur in the fully phase separated system are fully metallic and superconducting with higher critical temperatures than alkali-intercalated MoS${}_2$.

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References in corpus (1)

• Quantum ESPRESSO: a modular and open-source software project for quantum simulations of materials

Cited by in corpus (2)

• New High-Pressure Phases of MoSe${}_2$ and MoTe${}_2$
• High pressure layered structure of carbon disulfide