High pressure effect on structure, electronic structure and thermoelectric properties of MoS$_2$

TL;DR

This study investigates how high pressure influences the structural, electronic, and thermoelectric properties of MoS₂, revealing a transition from semiconductor to metal and enhanced thermoelectric performance, offering new ways to optimize these materials.

Contribution

It provides a comprehensive first-principles analysis of pressure-induced changes in MoS₂, highlighting a structural transition and improved thermoelectric properties under high pressure.

Findings

Structural anisotropy vanishes at 25 GPa.

Transition from semiconductor to metal at 25 GPa.

Enhanced thermoelectric figure of merit under pressure.

Abstract

We systematically study the effect of high pressure on the structure, electronic structure and transport properties of 2H-MoS$_2$, based on first-principles density functional calculations and the Boltzmann transport theory. Our calculation shows a vanishing anisotropy in the rate of structural change at around 25 GPa, in agreement with the experimental data. A conversion from van der Waals(vdW) to covalent-like bonding is seen. Concurrently, a transition from semiconductor to metal occurs at 25 GPa from band structure calculation. Our transport calculations also find pressure-enhanced electrical conductivities and significant values of the thermoelectric figure of merit over a wide temperature range. Our study supplies a new route to improve the thermoelectric performance of MoS$_2$ and of other transition metal dichalcogenides by applying hydrostatic pressure.