Pressure-induced permanent metallization with reversible structural transition in molybdenum disulfide

This report presents a pressure-induced permanent metallization for MoS 2 under non-hydrostatic conditions. Impedance and Raman spectra were measured to study the pressure-induced structural and electronic transformations of MoS 2 at up to ∼25 GPa in diamond anvil cells under both non-hydrostatic and hydrostatic conditions. The results show evidence for isostructural hexagonal distortion from 2 Hc to 2 Ha and metallization at ∼17 GPa and ∼20 GPa under non-hydrostatic and hydrostatic conditions, respectively. Interestingly, the metallization is irreversible only under non-hydrostatic compression. We attribute this phenomenon to the incorporation of molecules of pressure medium between layers, which mitigate compressed stress and reduce interlayer interaction.