# Prediction of Two-Dimensional Monochalcogenides: MoS and WS

## TL;DR

This study uses density functional theory to investigate the stability, bonding, and electronic properties of two novel two-dimensional monochalcogenides, MoS and WS, revealing their potential as stable, non-magnetic metallic or semi-metallic materials with strain-tunable electronic transitions.

## Contribution

First theoretical exploration of MoS and WS monolayer structures, predicting their stability, bonding nature, and electronic properties using density functional theory.

## Key findings

- Buckled structures are stable for both MoS and WS.
- WS puckered structure shows dynamical instability.
- MoS exhibits non-magnetic metallic behavior in stable forms.

## Abstract

Using density functional theory, we explore the possibility of two monolayer monochalcogenides, namely, MoS and WS (buckled and puckered). Our results on cohesive energy and phonon dispersion predict that the buckled structures of both MoS and WS are stable. On the other hand, while the puckered structure of WS clearly shows a dynamical instability, the same for MoS may have a stable configuration. Charge analyses predict ionic-like bonding in these systems. Density of states and band structure reveal a non-magnetic metallic nature for MoS in the stable configurations. However, for the buckled WS, our study predicts a non-magnetic semi-metallic nature. Further, semi-metal to indirect semiconductor transition has been observed for tensile strain of 5%, 6% and 8%.