Defect-induced 4p -magnetism in layered platinum diselenide

Platinum diselenide (${\mathrm{PtSe}}₂$) is a recently-discovered extrinsic magnet, with its magnetism attributed to the presence of Pt vacancies. The host material to these defects itself displays interesting structural and electronic properties, some of which stem from an unusually strong interaction between its layers. To date, it is not clear how the unique intrinsic properties of ${\mathrm{PtSe}}₂$ will affect its induced magnetism. In this theoretical work, we show that the defect-induced magnetism in ${\mathrm{PtSe}}₂$ thin films is highly sensitive to: (i) defect density, (ii) strain, (iii) layer thickness, and (iv) substrate choice. These different factors dramatically modify all magnetic properties, including the magnitude of local moments, strength of the coupling, and even nature of the coupling between the moments. We further show that the strong interlayer interactions are key to understanding these effects. A better understanding of the various influences on magnetism can enable controllable tuning of the magnetic properties in Pt-based dichalcogenides, which can be used to design novel devices for magnetoelectric and magneto-optic applications.