Electronic properties of dicalcium nitride (Ca₂N) nanoribbons from first principles

Electrides have confined electrons, which act as anions, in their cavities or interlayer space. They have exotic properties such as low work functions, charge transfer characteristics, and resistance anisotropy. Two-dimensional (2D) electrides, such as Ca₂N, Y₂C, and Gd₂C, have two-dimensional electron gas on their surface. In our previous studies, we reported the electronic properties of the surfaces of electrides. [1,2] After studying the electronic structure of the bulk and few-layer systems of electrides, the next topic to be addressed is the physical properties of the edges of the electrides. It was found that even in the case of graphene, various physical properties appear depending on the width and shape of the edge of the nanoribbon. In this talk, we will present the structure and electrical properties of single-layer Ca₂N nanoribbons. Two types of ribbons are considered: the Ca-terminated ribbon and the N-terminated ribbon. Interestingly, the N-terminated ribbon becomes thinner at the edge as the edge is rearranged and reorganized into a form with Ca atoms coming to the edge. In contrast, the Ca-terminated ribbon has no noticeable structural change. The Ca₂N monolayer is nonmagnetic, but its nanoribbons are all antiferromagnetic. Finally, we provide scanning tunneling microscopy images.