Lead Monoxide: Two-Dimensional Ferromagnetic Semiconductor Induced by Hole-Doping
We employ first-principles calculations to demonstrate ferromagnetic ground states for single- and multi-layer lead monoxide (PbO) under hole-doping, originating from a van Hove singularity at the valence band edge. Both the sample thickness and applied strain are found to have big effects on the electronic and magnetic properties. Multi-layer PbO is an indirect band gap semiconductor, while a direct band gap is realized in the single-layer limit. In hole-doped single-layer PbO biaxial tensile strain can enhance the stability of the ferromagnetic state.