Dirac State in the FeB2 Monolayer with Graphene-Like Boron Sheet.

By introducing the commonly utilized Fe atoms into a two-dimensional (2D) honeycomb boron network, we theoretically designed a new Dirac material of FeB2 monolayer with a Fermi velocity in the same order of graphene. The electron transfer from Fe atoms to B networks not only effectively stabilizes the FeB2 networks but also leads to the strong interaction between the Fe and B atoms. The Dirac state in FeB2 system primarily arises from the Fe d orbitals and hybridized orbital from Fe-d and B-p states. The newly predicted FeB2 monolayer has excellent dynamic and thermal stabilities and is also the global minimum of 2D FeB2 system, implying its experimental feasibility. Our results are beneficial to further uncovering the mechanism of the Dirac cones and providing a feasible strategy for Dirac materials design.