Electronic and optical properties of boron nitride nanoribbons in electric field by the tight-binding model

The tight-binding model is used to study the electronic and optical properties of armchair and zigzag boron nitride nanoribbons (ABNNRs and ZBNNRs) in electric field. Electric field could significantly change dispersion relations, degeneracy, edge-states, band crossings, and energy gaps. The field-modulation of energy gaps is more effective and covers wider energy range for BNNRs than graphene nanoribbons. The critical electric field that induces zero-gap transition strongly depends on geometric structures of BNNRs. At zero field, the selection rule and the absorption frequency range of spectral functions are different between ABNNRs and ZBNNRs. Electric field would change state functions that constructs new selection rule and further exhibits more absorption peaks.