From semiconductor to metal: A reversible tuning of electronic properties of mono to multilayered SnS$_\mathrm{2}$ under applied strain

TL;DR

This study demonstrates that the electronic properties of SnS₂ can be reversibly tuned from semiconductor to metal through applied biaxial and normal strains, enabling customizable electronic behavior in 2D materials.

Contribution

The paper reveals that SnS₂'s electronic structure can be reversibly controlled by strain, showing a semiconductor-metal transition at specific strain thresholds, which is distinct from other 2D materials like MoS₂.

Findings

SnS₂ undergoes a reversible semiconductor-metal transition at specific strain values.

The critical strain for transition varies with strain type due to different orbital interactions.

SnS₂'s transition threshold is higher under normal compressive strain compared to MoS₂.

Abstract

Controlled variation of the electronic properties of 2D materials by applying strain has emerged as a promising way to design materials for customized applications. Using first principles density functional theory calculations, we show that while the electronic structure and indirect band gap of SnS$_\mathrm{2}$ do not change significantly with the number of layers, they can be reversibly tuned by applying biaxial tensile (BT), biaxial compressive (BC), and normal compressive (NC) strains. Mono to multilayered SnS$_\mathrm{2}$ exhibit a reversible semiconductor to metal transition (S-M) at strain values of 0.17, $-$0.26, and $-$0.24 under BT, BC, and NC strains, respectively. Due to weaker interlayer coupling, the critical strain value required to achieve S-M transition in SnS$_\text{2}$ under NC strain is much higher than for MoS$_\mathrm{2}$. The S-M transition for BT, BC, and NC strains is caused by the interaction between the S-$p_z$ and Sn-$s$, S-$p_x$/$p_y$ and Sn-$s$, and S-$p_z$ and Sn-$s$ orbitals, respectively.