Cubine, a superconducting 2-dimensional copper-bismuth nano sheet

We report on the discovery of a 2-dimensional copper-bismuth nano sheet from \textit{ab initio} calculations, which we call cubine. According to our predictions, single layers of cubine can be isolated from the recently reported high-pressure CuBi bulk material (metastable at ambient conditions) at an energetic cost of merely $\approx 20$~meV/\AA$^2$, comparable to separating single layers of graphene from graphite. Our calculations suggest that cubine has remarkable electronic and electrochemical properties: It is a superconductor with a moderate electron-phonon coupling $\lambda=0.5$, leading to a $T_c$ of $\approx1$~K, and can be readily intercalated with lithium with a high diffusibility, rendering it a promising candidate material as an anode in lithium-ion batteries.