Influence of the Hubbard U Parameter on the Structural, Electronic, Magnetic, and Transport Properties of Cr/Fe/Zr-Based MBenes

Although relatively new, MBenes are gaining prominence due to their outstanding mechanical, electronic, magnetic, and chemical properties, and they are predicted to be good electrodes for catalytic processes as well as robust 2D magnets with high critical temperatures, to mention some of their intriguing attributes. From all their multiple stoichiometries, a theoretical study of their orthorhombic and hexagonal phases in the framework of density-functional theory is performed in this work. The results suggest that their properties are strongly dependent on the initial conditions considered in the theoretical approach and must be treated with caution. However, and independently of these factors, all of them are demonstrated to be energetically stable, show a metallic behavior, and exhibit, in specific cases, large magnetic moments per unit cell, exceeding 6.5 μB in the case of the orthorhombic-type Cr2B2, making them suitable as robust 2D magnets with room critical temperature. These findings represent an important step toward a better understanding of MBenes, opening several windows to future research in energy conversion and storage, sensing, catalysis, biotechnology, or spintronics.