Nontrivial Metallic State of Molybdenum Disulfide

TL;DR

This study investigates the high-pressure metallic state of MoS₂, revealing an anomaly in resistance linked to a possible charge density wave and potential superconductivity emergence.

Contribution

It provides new insights into the pressure-induced structural and electronic transitions in MoS₂, suggesting a charge density wave state and possible superconductivity.

Findings

Resistance anomaly shifts with pressure

Appearance of a new Raman phonon mode

Potential for superconductivity at higher pressures

Abstract

The electrical conductivity and Raman spectroscopy measurements have been performed on MoS$_2$ at high pressures up to 90 GPa and variable temperatures down to 5 K. We find that the temperature dependence of the resistance in a metallic 2H$_a$ phase has an anomaly (a hump) which shifts with pressure to higher temperature. Concomitantly, a new Raman phonon mode appears in the metallic state suggesting that the electrical resistance anomaly may be related to a structural transformation. We suggest that this anomalous behavior is due to a charge density wave state, the presence of which is indicative for a possibility for an emergence of superconductivity at higher pressures.