HfXO (X = S and Se) Janus monolayers as promising two-dimensional platforms for optoelectronic and spintronic applications

In this work, the oxygen containing HfXO (X = S and Se) Janus monolayers are explored using first-principles calculations. Phonon calculations and ab initio molecular dynamic simulations are used to examine their stability. The charge transfer generates a predominant ionic character in HfSO and HfSeO monolayers, which exhibit wide gap semiconductor nature. In addition, efficient approaches are proposed to induce novel features. Specifically, applying external strain may effectively tune the electronic band gap, enhancing significantly the absorption in visible regime. Besides, doping with manganese (Mn) leads to a significant magnetization, where magnetic properties are produced mainly by dopant and its first X neighbor atoms. Feature-rich magnetic semiconductor nature app ears at low doping level. Further studying magnetic properties indicates that the magnetic phase transition may occur depending on the doping configuration. Our work recommends HfXO Janus monolayers as prospective 2D platform materials to be applied in high-performance nanoscale optoelectronic and spintronic devices.