Doping Janus MoSSe monolayer with Al/Ga and P/As atoms, and their clusters: effective methods for the band structure and magnetism engineering

Abstract

In this work, new doping approaches are proposed towards effective band structure and magnetism engineering of Janus MoSSe monolayer. In its pristine form, MoSSe monolayer is a direct gap semiconductor. Magnetic semiconductor nature is obtained by doping with Al/Ga atoms at Mo sublattice and P atom at S sublattice. Herein, overall magnetic moments of 3.00/2.96 and 1.00 μ_B are obtained, respectively. Moreover, the spin-polarized states are produced primarily by the first neighboring Mo atoms from doping site and P impurity, respectively. Meanwhile, As doping metallizes the monolayer, maintaining its nonmagnetic nature. Similarly, no magnetism is induced by doping with AlP₃, AlAs₃, GaP₃, and GaAs₃ binary clusters. However, the substitution of these clusters causes large band gap reduction up to 78.85%, which can be attributed to new mid-gap subands formed mainly by Mo atoms. Further, doping with AlPAs/GaPAs and AlP₃As₃/GaP₃As₃ ternary clusters is also considered. In these cases, magnetic semiconductor and half-metallic natures are obtained, respectively, which are regulated primarily by Mo atoms. Further, Bader charge analysis is carried out to investigate the interactions between impurities/clusters with the host monolayer. Results demonstrate the charge gainer role of Al and Ga atoms, meanwhile P and As impurities act as charge gainer. Our findings may suggest the prospect of the proposed doping approaches to functionalize Janus MoSSe monolayer towards spintronic and optoelectronic applications.