Spin-polarized two-dimensional electron/hole gases on LiCoO${}_2$ layers

Abstract

First-principles calculations show the formation of a 2D spin polarized electron (hole) gas on the Li (CoO${}_2$) terminated surfaces of finite slabs down to a monolayer of LiCoO${}_2$ in remarkable contrast with the bulk band structure stabilized by Li donating its electron to the CoO${}_2$ layer forming a Co-$d-t_{2g}^6$ insulator. By mapping the first-principles computational results to a minimal tight-binding models corresponding to a non-chiral 3D generalization of the quadripartite Su-Schriefer-Heeger (SSH4) model, we show that these surface states have topological origin.