Electronic and magnetic properties of freestanding 3d transition metal-doped χ3 borophene: A density functional theory study

Abstract

The emergence of borophene and its polymorphic phases has opened new possibilities in advanced technologies. Recent experimental studies have demonstrated the potential to synthesize freestanding ${\beta }_{12}$ and ${\chi }_3$ phases through methods such as mechanical and liquid phase exfoliation. In this work, we focus on the ${\chi }_3$ phase of borophene. Using first-principles calculations, we investigated the properties of ${\chi }_3$ borophene monolayers doped with 3d transition metals, namely Cr, Mn, Fe, Co, and Ni. The transition metal (TM) atoms were found to integrate well into the ${\chi }_3$ structure, with variations in electronic and magnetic properties depending on the type of impurity atom and its geometric position within the lattice. Cr and Mn doping produced the highest magnetization levels—2.83 ${\mu }_B$ and 3.13 ${\mu }_B$, respectively. Notably, the material retained its metallic character even at high concentrations of Cr and Mn atoms. Furthermore, the observed long-range interactions between the impurity atoms in the doubly-doped structures suggest the potential for indirect magnetic spin coupling. These findings offer valuable insights into the properties of 3d TM-doped freestanding ${\chi }_3$ borophene, highlighting its potential for applications in spintronics, magnetic storage devices, and other advanced nanotechnologies.