Tuning electronic structure of SnS 2 nanosheets by vertical electric field: a first-principles investigation

Based on density functional theory, we investigated band gap tuning in transition-metal dichalcogenides SnS 2 nanosheets by external electric fields applied perpendicular to the layers. We show that the fundamental band gap value of 2H and 4H SnS 2 multilayer structures continuously decreases with increasing strength of applied electric fields, eventually rendering them metallic. We interpret our results in the light of the giant Stark effect and obtain a robust relationship, which is essentially characterized by the interlayer spacing, for the rate of band gap change with applied external field. And it is also valid for monolayer structure, though it need very large electric filed to make the gap change.