First-Principles Study of the Electronic Properties of B/N Atom Doped Silicene Nanoribbons

On the basis of first-principles calculations, we study the geometric, electronic, and magnetic properties of silicene nanoribbons (SiNRs) doped by the boron/nitrogen (B/N) bonded pair at different sites. Total energies analysis indicate that the B/N pair tends to be doped at the edge of SiNRs and that the B/N pair doping in the armchair SiNRs (ASiNRs) is easier to carry out than the unbonded B/N pair doping in ASiNRs. Different from the metallic states associated with the singly substituted N or B atom at the edge in ASiNRs, the B/N bonded pair doping results in a semiconducting character, where the energy gap of ASINR can be adjusted, dependent on the B/N pair doping sites in ASiNR. For zigzag SiNRs (ZSiNRs), the introduction of the B/N pair results in a transition from nonmagnetic to spin-polarized states, which is attributed to the perturbation of pi and pi states localized at the doped ZSiNR edge. More importantly, the marvelous spin gapless semiconductor character with 100% spin polarized currents around the Fermi level has been obtaind, when the substitutional B/N pair located at the edge or subedge sites in ZSiNIts. These findings present a possible avenue for energy band and magnetism engineering in SiNR and benefit the design of silicene-based electronic devices.