The impact of spin–orbit coupling and the strain effect on monolayer tin carbide

Two-dimensional tin carbide (2D-SnC) has attracted intensive attention from researchers recently due to its superior properties. We focus herein on the impact of the effects of spin–orbit coupling (SOC) and strain on the properties of 2D-SnC by using density functional theory (DFT). The electronic band structure of 2D-SnC confirms that it has an indirect bandgap of ~ 1.246 eV, which decreases to ~ 1.12 eV after introducing the SOC effect. The bandgap widens with increasing applied compressive strain but narrows with increasing applied tensile strain. A transition from an indirect to direct bandgap is observed at 6% compressive strain when excluding the SOC effect, whereas a direct bandgap is formed at 5% compressive strain when including the SOC effect. The structure of 2D-SnC is dynamically robust because it can tolerate a significant amount of biaxial strain. It is found that the peaks of the dielectric constant of 2D-SnC shift to higher photon energy (blue-shift) when the applied compressive strain is increased. In contrast, they shift to lower photon energy (red-shift) when the applied tensile strain is increased. Such strategies for tuning the bandgap of 2D-SnC based on the SOC effect and application of biaxial strain may pave the way for its use in future optoelectronic and spintronic device applications.