Two-Dimensional Oxide Topological Insulator With LiFeAs Structure

Using first-principles calculations, we propose that ZrSiO can be viewed as a three-dimensional (3D) oxide weak topological insulator (TI) with Z$_{2}$ idiocies (0; 001). Further calculations show that the single layer of such material is a long-sought-after 2D oxide TI with a band gap around 10 meV. Furthermore, we also find that there are many other isostructural compounds, which can host similar electronic structure and form a `WHM' material family with `W' being Zr, Hf or La, `H' being group IV or group V element, and `M' being group VI one.