The structural and electronic properties of BC6N multilayers: A first-principles study

The electronic properties of two-dimensional (2D) multilayer materials can be finely tuned through interlayer twisting or sliding, leading to fascinating physical phenomena such as superconductivity and ferroelectricity. For emerging 2D materials, determining the stable multilayer structures is a crucial first step in achieving desired electronic properties through interlayer geometric designs. Herein, we conduct first-principles calculations to investigate the intricate stacking behaviors and electronic properties of BC6N bilayers and multilayers. For each of the three distinct BC6N monolayers, we identified the most energetically favorable bilayer stacking arrangement. These bilayers share similar structural characteristics in the positioning of Band N atoms between layers, which can be qualitatively understood in terms of Coulomb interactions. Furthermore, the interlayer distances of BC6N multilayers with ABAB & ctdot; stacking pattern show varying degrees of reduction as the number of layers increases. Band structure calculations reveal that the band gaps of these BC6N multilayers decrease as the number of layers increases due to interlayer Coulomb screening effect, and a direct-to-indirect band gap transition occurs when these multilayers approach their corresponding bulk phases. Our investigation provides fundamental and useful insights for further studies of BC6N multilayers.