Effect of vacancy and pyridinic-like X-atom (X = Mg, B, C, and N) doping on the electronic and magnetic properties of antimonene: First-principles insights

Abstract

We have explored the effect of vacancy and pyridinic-like X-atom (X = Mg, B, C, and N) doping on the geometries, electronic structure, and magnetism of antimonene (Sb) by means of first-principles calculations. The results showed that Sb with a single vacancy (SV-Sb) becomes a ferromagnetic metal with a moment of 0.33 µB. The X-atoms were doped at the edge site of the SV-Sb to form SV-nX-Sb (n = 1, 2, 3). All doped atoms except Mg form strong bonds with neighboring Sb-atoms. The stability of the designed structures was verified from formation energy (Efor). It was found that the SV-1X-Sb system is energetically more favorable (i.e. has the lowest Efor) for X = Mg, B, and C, while SV-3N-Sb is found more stable than SV-1N-Sb and SV-2N-Sb. Unlike metallic SV-Sb, the SV-1Mg-Sb, SV-1B-Sb, SV-1 C-Sb, and SV-3N-Sb structures exhibit semiconducting properties with a small band gap (of less than 0.5 eV). The ferromagnetism of SV-Sb is retained for X = B, and N doping, whereas Mg and C doping turned SV-Sb to non-magnetic, caused by the reconstruction of the edge Sb/X atoms. In addition, selective doping significantly altered the work function of the host material. These findings suggest the potential use of non-magnetic elements for tuning the electronic and magnetic properties of the monolayer antimonene for extended applications.