Inducing high- Tc ferromagnetism in the van der Waals crystal Mn(ReO4)2 via charge doping: A first-principles study

Abstract

Magnetic van der Waals (vdW) materials, which can serve as ideal platforms to study low-dimensional magnetism and possess potential applications in next-generation spintronic devices, have attracted intensive attention recently. Here, based on density functional theory calculations we predict that the electron-doped $\mathrm{Mn}{({\mathrm{ReO}}_{4})}_{2}$ (MRO) with an undulating layered structure is a ferromagnetic (FM) vdW material. Our calculations show that the magnetic interaction between two nearest-neighboring Mn atoms in the undoped MRO is very weak due to the long distance between the Mn atoms separated by the nonmagnetic ${\mathrm{ReO}}_{4}$ tetrahedra. With moderate electron doping from charge injection or K intercalation, the Re atoms become spin polarized. Thus, an effective FM coupling between the Mn atoms can be induced via the Mn-O-Re antiferromagnetic superexchange, while the calculated ${T}_{c}$ can exceed room temperature. The electron-doped MRO not only takes the advantage of strong FM interaction as double perovskites, but also avoids the shortage of the antisite disorder. The calculated small cleavage energy and stable phonon spectra indicate that MRO can be exfoliated to thin films, which facilitates its surface modification. Our paper on MRO, thus, provides a template to realize ferromagnetism in vdW materials with multitype transition metals.