TM2B3 monolayers: Intrinsic anti-ferromagnetism and Dirac nodal line semimetal

Searching for two-dimensional materials combining both magnetic order and topological order is of great significance for quantum devices and spintronic devices. Here, a class of two-dimensional transition metal borides, TM2B3 (TM = Ti–Ni), with high stability and stable antiferromagnetic (AFM) orders was predicted by using the first-principles method. The result shows that they possess large magnetic anisotropy energy and high critical temperature. Interestingly, Mn2B3 monolayer is confirmed to be AFM Dirac node line semimetal with several Dirac points near the Fermi level. Detailed analysis of the irreducible representations shows that the nodal lines are protected by the horizontal mirror symmetry Mz. Our findings provide an excellent platform for exploring topological and magnetic materials ready for the next generation of spintronic devices.