Abstract
In this study, we investigated the electronic and optical properties of a Janus PtSTe monolayer under the effect of an external electric field and biaxial strain. Monolayer PtSTe was found to be a semiconductor with an indirect band gap of 0.93 eV. For compressive strain, the band gap of PtSTe decreased to -8% strain, where a semiconductor to semimetal phase transition took place. Under tensile strain, the PtSTe band gap increased up to 2% strain, and for greater strain, the band gap started to decrease. Interestingly, at strain >= 8%, a quasi-direct band gap was observed. A negative external electric field decreases the band gap continuously, whereas a positive field increases the band gap. The absorption intensity of monolayer PtSTe was significantly altered by biaxial strain, while it was almost unaffected by the external electric field. Our results provide information about the flexibility of tuning the electronic and optical properties of this material for different technological applications.