Multiple Control of Few-layer Janus MoSSe Systems

TL;DR

This study uses density functional theory to explore how electric fields, strain, and stacking affect the electronic properties of multi-layer Janus MoSSe systems, revealing tunable phase transitions, rectification, and layer-dependent effects.

Contribution

It provides new insights into the tunability of electronic and transport properties of 4-layer MoSSe junctions under various external influences.

Findings

Electric field induces metal-semiconductor transition.

Rectification ratio reaches 34.1 in Zr/4-layer MoSSe/Zr junction.

Odd-even layer effect on electron transmission.

Abstract

In this computational work based on density functional theory we study the electronic and electron transport properties of asymmetric multi-layer MoSSe junctions, known as Janus junctions. Focusing on 4-layer systems, we investigate the influence of electric field, electrostatic doping, strain, and interlayer stacking on the electronic structure. We discover that a metal to semiconductor transition can be induced by an out-of-plane electric field. The critical electric field for such a transition can be reduced by in-plane biaxial compressive strain. Due to an intrinsic electric field, a 4-layer MoSSe can rectify out-of-plane electric current. The rectifying ratio reaches 34.1 in a model junction Zr/4-layer MoSSe/Zr. This ratio can be further enhanced by increasing the number of MoSSe layers. In addition, we show a drastic sudden vertical compression of 4-layer MoSSe due to in-plane biaxial tensile strain, indicating a second phase transition. Furthermore, an odd-even effect on electron transmission at the Fermi energy for Zr/$n$-layer MoSSe/Zr junctions with $n=1, \, 2,\, 3, \,\dots,\, 10$ is observed. These findings reveal the richness of physics in this asymmetric system and strongly suggest that the properties of 4-layer MoSSe are highly tunable, thus providing a guide to future experiments relating materials research and nanoelectronics.