First-principles study of stability, electronic structure and magnetic properties of Be2C nanoribbons

Abstract First-principles calculations are carried out to investigate the stability, electronic structure and magnetic properties of Be 2 C nanoribbons (Be 2 C-NRs) with their ribbon axis along the a and b axes. It is found that except for b -Be 2 C-NR with the C site terminated edge, a -Be 2 C-NRs and other b -Be 2 C-NRs possess good structural stabilities at room temperature. In addition, H passivation enables b -Be 2 C-NR with C site terminated edge to stabilize at room temperature by saturating the dangling bonds at edges. Furthermore, stable a -Be 2 C-NRs and b -Be 2 C-NRs are all nonmagnetic semiconductors and their band gaps are significantly dependent on the edge configuration and the ribbon width. In contrast, H passivated b -Be 2 C-NR with C site terminated edge is half-metallic with a magnetic ground state, irrespective of the ribbon width. In particular, H passivated b -Be 2 C-NR with C site terminated edge has a strong intra-edge ferromagnetic coupling interaction in the ground state, and an inter-edge ferromagnetic interaction is found in small-width H passivated nanoribbon. The calculated density of states and the spin density distribution show that the p–p hybridization interaction involving polarized electrons is responsible for intra-edge and inter-edge ferromagnetic coupling.