First-principles prediction of moire ultra-flat bands in twisted bilayer nitrogene

Based on first-principles density functional theory, we investigated the electronic structures of twisted bilayer nitrogene at various twist angles. This electron localization by the influence of the moir & eacute; superlattice with very small theta leads to flat bands, especially one of valence bands at the Fermi level on atoms in the AA zone whereas for a larger theta no strong localization occurs owning to a large proportion of the AB zone. Also, there is a linear relationship between the band gaps and the torsion angles of the twisted bilayer nitrogene. A smaller twist angle corresponds to a larger band gap, whereas a larger twist angle corresponds to a smaller band gap. This localization should also reduce considerably the mobility of the electrons and thus modify transport properties.