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

• Main Author: Santosh Kumar Radha, Walter R. L. Lambrecht
• Format: Article
• Language: English
• Published: SciPost 2021-03-01
• Series: SciPost Physics
• Online Access: https://scipost.org/SciPostPhys.10.3.057

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, in remarkable contrast with the bulk band structure, which is 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-Schrieffer-Heeger (SSH4) model and symmetry analysis, we show that these surface states have topological origin.