Moiré M-Nitridanes (M = Al, B, Ga) Analogues of Carbon Diamanes: Ab Initio Investigation of Atomic Structures, Electronic, and Mechanical Properties

Abstract

With an emphasis on remarkable properties, twisted vertical heterostructures have received particular attention in experimental and theoretical works. They have promising unknown effects in science and technology. These twisted systems can be considered a platform for the formation of crystalline film structures. In this paper, we consider one of them, diamond-like crystals with Moiré atomic structure formed from twisted two-dimensional hexagonal layers. Analogues of carbon Moiré diamanes are nanometer-thick films obtained by both stacking and twisting near 30° of two functionalized monolayers of nitrides (AlN, BN, GaN), which have already been actually obtained. We study their energetically stable atomic configurations and electronic and elastic properties. The proposed hydrogenated and/or fluorinated (second side, Janus structures) Moiré nitridane nanostructures with a twisted angle of 27.8° possess a wide band gap from 3 to 4 eV. Electronic band structures are characterized by many flattened bands located near the edges of the valence and conduction bands, which tend to be signatures of Moiré superlattices. The Moiré nitridanes can be used as a base for two-dimensional semiconductors with low-dispersive flattened bands and strong localization of the electronic states, which should increase the probability of their resonant IV characteristics and light excitations. Thus, the circumstance is useful for nano- and optoelectronic resonant devices. In addition, it was found that hydrogenated and fluorinated Moiré nitridane and nitride films have some very different elastic responses, which are attractive for mechanoelectric applications.