First-Principles Prediction Of Moiré Ultra-Flat Bands In Twisted Bilayer Nitrogene

Abstract

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 Moiré superlattice with very small θ leads to flat bands, especially one of valence bands at the Fermi level on atoms in the AA zone whereas for a larger θ 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.

Keywords: Moiré pattern, twist angles, flat band, electron localization