Vacancy‐ and doping‐dependent electronic and magnetic properties of monolayer SnS2

We have performed first‐principles calculations to investigate the formation and migration of vacancies and doping with M (M = Ti, V, Co, Mo, W, Re) at the Sn sites and X (X = O, Se, Te) at the S sites in monolayer SnS2. We find that the formation energies for S vacancy under both Sn‐ and S‐rich environments are lower than those for Sn vacancy, indicating that the vacancies at the S sites are likely to be formed during the synthesis. Reducing the possibility of vacancy cluster formation, both the vacancies at the Sn and S sites remain robust due to high migration barrier. Additionally, SnS2 with the vacancies at the Sn sites induces magnetic ground states with a magnetic moment of 4.00 μB. Both the Sn‐ and S‐sites vacancies preserve the semiconducting nature of pristine SnS2 with band gaps of 2.47 eV and 0.30 eV, respectively. Furthermore, we find that the dopants Ti, V, Mo, W, Re can be easily incorporated at the Sn sites in monolayer SnS2 due to the low formation energies under the S‐rich environment. However, Co may not be easily incorporated into SnS2. The doping with M at the Sn sites induces magnetic ground states in non‐magnetic SnS2. Additionally, a long‐range magnetic ordering is observed in SnS2 doped with V, Co, and Mo. In contrast, easy incorporation of O, Se, and Te at the S sites under the Sn‐rich environment has been observed while the semiconducting nature of SnS2 preserves with small band gaps.