Two-Dimensional Transition Metal Boron Cluster Compounds (MBnenes) with Strain-Independent Room-Temperature Magnetism

Two-dimensional (2D) metal borides (MBenes) with unique electronic structures and physicochemical properties hold great promise for various applications. Given the abundance of boron clusters, we proposed employing them as structural motifs to design 2D transition metal boron cluster compounds (MB_nenes), an extension of MBenes. Herein, we have designed three stable MB_nenes (M₄(B₁₂)₂, M = Mn, Fe, Co) based on B₁₂ clusters and investigated their electronic and magnetic properties using first-principles calculations. Mn₄(B₁₂)₂ and Co₄(B₁₂)₂ are semiconductors, while Fe₄(B₁₂)₂ exhibits metallic behavior. The unique structure in MB_nenes allows the coexistence of direct exchange interactions between adjacent metal atoms and indirect exchange interactions mediated by the clusters, endowing them with a Néel temperature (T_N) up to 772 K. Moreover, both Mn₄(B₁₂)₂ and Fe₄(B₁₂)₂ showcase strain-independent room-temperature magnetism, making them potential candidates for spintronics applications. The MB_nenes family provides a fresh avenue for the design of 2D materials featuring unique structures and excellent physicochemical properties.