Confined anionic electrons and their effect on physical properties of Ca₂N bilayers with different stacking configurations

Ca₂N is a unique two-dimensional material due to its confined anionic electrons. Unlike three-dimensional materials, the framework of Ca₂N effectively confines the anionic electrons, leading to interesting physical and chemical properties. To study the electrical and optical properties of Ca₂N bilayers with various stacking configurations, we used density functional theory calculations. This approach allowed us to investigate the behavior of anionic electrons located at the interlayer interface and at the surface. Using maximally localized Wannier functions to extract tight-binding parameters for each stacking configuration, we determined Hofstadter's butterfly patterns for each structure, which provide a valuable insight into the influence of an external magnetic field on the electronic band structure. This work paves the way for further exploration of experimentally feasible configurations and their potential applications.