Vacancy-and doping-mediated electronic and magnetic properties of PtSSe monolayer towards optoelectronic and spintronic applications

Abstract

Developing new multifunctional two-dimensional (2D) materials with two or more functions has been one of the main tasks of materials scientists. In this work, defect engineering is explored to functionalize PtSSe monolayer with feature-rich electronic and magnetic properties. Pristine monolayer is a non-magnetic semiconductor 2D material with a band gap of 1.52(2.31) eV obtained from PBE(HSE06)-based calculations. Upon creating single Pt vacancy, the half-metallic property is induced in PtSSe monolayer with a total magnetic moment of 4.00 μ_B. Herein, magnetism is originated mainly from S and Se atoms around the defect site. In contrast, single S and Se vacancies preserve the non-magnetic nature. However, the band gap suffers of considerable reduction of the order of 67.11% and 48.68%, respectively. The half-metallicity emerges also upon doping with alkali metals (Li and Na) with total magnetic moment of 1.00 μ_B, while alkaline earth impurities (Be and Mg) make new diluted magnetic semiconductor materials from PtSSe monolayer with total magnetic moment of 2.00 μ_B. In these cases, magnetic properties are produced mainly by Se atoms closest to the doping site. In addition, doping with P and As atoms at chalcogen sites is also investigated. Except for the half-metallic As_Se system (As doping at Se site), the diluted magnetic semiconductor behavior is obtained in the remaining cases. Spin density results indicate key role of the VA-group impurities in magnetizing PtSSe monolayer. In these cases, total magnetic moments between 0.99 and 1.00 μ_B are obtained. Further Bader charge analysis implies the charge loser role of all impurities that transfer charge to the host monolayer. Results presented in this work may suggest promises of the defected and doped Janus PtSSe structures for optoelectronic and spintronic applications.