Modulating electronic structure of monolayer SnSe via applying external constant potential

Using a first-principles approach, we studied electronic structure modulation in monolayer SnSe. Our results show the fundamental band gap size can be tuned via applying external constant potential (ECP) to muffin-tin spheres. At ECP of 0.9 Ry, semiconductor-metal transition appears, and a new type of nearly linear dispersions occur at band edge. We theoretically propose a new strategy to tune the band gap and obtain nearly linear dispersions in monolayer SnSe, which can inspire more experimental and further theoretical research works.