Changing the Electronic and Magnetic Properties of Monolayer HfS2 by Doping and Vacancy Defects: Insight from First‐Principles Calculations.

The effects of various vacancies and group‐VIB and VIIB transition metal substitutional doping on the structural, electronic, and magnetic properties of monolayer HfS2 are studied by first‐principles calculations. The results show that pristine monolayer HfS2 is a nonmagnetic semiconductor; it becomes a metal on creating a single V1Hf or V1S vacancy, whereas it is still a semiconductor on creating V1Hf+1S divacancy or V1Hf+2S trivacancy. The V1Hf single vacancy and V1Hf+1S divacancy induce magnetic moments of 3.265 and 2.000 μB, respectively, whereas the V1S single vacancy and V1Hf+2S trivacancy do not induce any magnetic moments. One of the group‐VIB and VIIB transition metal atoms substituting for one Hf atom in the monolayer HfS2 induces magnetic moments of about 2.000 and 3.000 μB, respectively. Furthermore, the spin‐polarized band structures show that the Cr‐doped monolayer HfS2 is a magnetic metal, whereas the Mn‐, Tc‐, and Re‐doped monolayer HfS2 are magnetic semiconductor. The Mo‐ and W‐doped monolayer HfS2 are magnetic half metal with wide spin‐down bandgaps of 0.975 and 1.074 eV, respectively, and thus can be used in nanoelectronics and spintronics devices. [ABSTRACT FROM AUTHOR]