Rich essential properties of boron, carbon, and nitrogen substituted germanenes

Binary compounds, fully B-/C-/N-substituted germanenes, exhibit the diversified phenomena through the different chemical bondings. The delicate first-principles calculations can present the buckling/planar honeycomb lattices, the atom-dominated band structures, the spatial charge densities, the spin density distributions, and the atom-, orbital-and spin-decomposed density of states, being very useful in determining the critical orbital hybridizations and magnetic configurations. The concise pictures, the strong competition between sp2 and sp3 bondings and the guest-dependent spin states, are responsible for the geometric symmetries, the metallic/wide-/narrow-gap behaviors, the modification/destruction of Dirac-cone structures, the non-or ferromagnetic properties; the crossings/anti-crossings of π and σ bands or the pure sp3 energy bands.