Role of Intrinsic Points Defects on the Electronic Structure of Metal-Insulator Transition h-FeS

Hexagonal iron sulfide (h-FeS) offers huge potential in the development of metal-insulator transition devices. A stoichiometric h-FeS is hard to obtain from its natural iron deficiency. The effect of this iron deficiency on the electronic properties is still obscure. Here, we performed a charged point defect calculation in h-FeS. We found that the most favorable point defect in h-FeS can be tuned with a proper synthesis environment. The single iron vacancy could induce a midgap state with 0.05 eV energy gap, which explains the h-FeS low experimental band gap value. Furthermore, a semiconductor-to-metal transition is observed in h-FeS with higher iron vacancy concentration showing better conductivity from the excess charges. We also observe that iron vacancies will induce a magnetic moment on E r the antiferromagnetic h-FeS. The findings that the induced MIT behavior and magnetic moment can be tuned by defect concentration may benefit the development of spintronics devices.

Automated summary

The study found that a single iron vacancy in hexagonal iron sulfide (h-FeS) could induce a midgap state, explaining the low experimental band gap value observed. A semiconductor-to-metal transition was observed in h-FeS with higher iron vacancy concentration showing better conductivity. Iron vacancies induced a magnetic moment on antiferromagnetic h-FeS, which could benefit the tuning of material's magnetic properties.