Nature of low dimensional structural modulations and relative phase stability in MoS2/WS2-ReS2 transition metal dichalcogenide alloys

TL;DR

This study investigates the structural modulations and phase stability of MoS2-ReS2 and WS2-ReS2 alloys, revealing phase transition points and how alloying influences electronic and structural properties in 2D materials.

Contribution

It provides the first detailed analysis of Peierls-like modulations and phase transitions in these alloys, highlighting new ways to tune their electronic structures.

Findings

Polytype phase transition occurs at ~50 at.% Mo/W in ReS2.

Distinct structural modulations observed at specific alloy compositions.

50% alloy system shows potential for metal-semiconductor transition.

Abstract

We report on the various types of Peierls like two dimensional structural modulations and relative phase stability of 2H and 1T poly-types in MoS2-ReS2 and WS2-ReS2 alloy system. Theoretical calculation predicts a polytype phase transition cross over at ~50 at.% of Mo and W in ReS2 in both monolayer and bulk form, respectively. Experimentally, two different types of structural modulations at 50% and a modulation corresponding to trimerization at 75% alloy composition is observed for MoS2-ReS2 and only one type of modulation is observed at 50% WS2-ReS2 alloy system. The 50% alloy system is found to be a suitable monolithic candidate for metal semiconductor transition with minute external perturbation. ReS2 is known to be in 2D Peierls distorted 1Td structure and forms a chain like superstructure. Incorporation of Mo and W atoms in the ReS2 lattice modifies the metal-metal hybridization between the cations and influences the structural modulation and electronic property of the system. The results offer yet another effective way to tune the electronic structure and poly-type phases of this class of materials other than intercalation, strain, and vertical stacking arrangement.