Effect of structural defects on electronic and magnetic properties in pristine and Cr-doped HfS2 monolayer

Abstract Based on density functional theory, we investigate electronic and magnetic properties of pristine and Cr-doped monolayer HfS 2 with vacancy defects. Nine possible vacancy defects types are considered. The results show that one hafnium (Hf) atom vacancy defect at monolayer HfS 2 (V 1Hf ) will induces to 1.824μ B magnetic moment and shows magnetic metallic property and the magnetic moments mainly comes from the nearest six S atom p orbitals. For two Hf atoms vacancy defects (V 2Hf ), the magnetic moment vanishes and the system shows semiconductor property. For the case of sulfur vacancy defects (V nS , n = 2, 3), all of these systems show magnetic metallic properties, and the total magnetic moment increases with increasing S vacancy defected atoms. When Hf+6S atoms are removed, the system is a magnetic metal with 0.501μ B magnetic moment. In addition, we find 2 V 2S and 1 V 3S have the most stable structures when two and three S atoms are removed, respectively. When one Cr atom substitutes Hf atom in V 1Hf , 2 V 2S and 1 V 3S systems ( 2 Cr + V 2S , 1 Cr + V 3S ), 2.332μ B , 2.806μ B and 3.501μ B magnetic moments are introduced, respectively. Cr atom is antiferromagnetic coupling to the nearest S atoms. These results show that S vacancy defects induce the charge redistribution of the nearest Hf atoms and appear the large charge polarization, thereby forming the larger local magnetic moment.