Tunable Magnetism and Extraordinary Sunlight Absorbance in Indium Triphosphide Monolayer

Atomically thin two-dimensional (2D) materials have received considerable research interest due to their extraordinary properties and promising applications. Here we predict the monolayered indium triphosphide (InP₃) as a new semiconducting 2D material with a range of favorable functional properties by means of ab initio calculations. The 2D InP₃ crystal shows high stability and promise of experimental synthesis. It possesses an indirect band gap of 1.14 eV and a high electron mobility of 1919 cm² V^-1 s^-1, which can be strongly manipulated with applied strain. Remarkably, the InP₃ monolayer suggests tunable magnetism and half-metallicity under hole doping or defect engineering, which is attributed to the novel Mexican-hat-like bands and van Hove singularities in its electronic structure. A semiconductor-metal transition is also revealed by doping 2D InP₃ with electrons. Furthermore, monolayered InP₃ exhibits extraordinary optical absorption with significant excitonic effects in the entire range of the visible light spectrum. All these desired properties render 2D InP₃ a promising candidate for future applications in a wide variety of technologies, in particular for electronic, spintronic, and photovoltaic devices.