Three-dimensional topological insulators in the octahedron-decorated cubic lattice

TL;DR

This paper studies a tight-binding model on an octahedron-decorated cubic lattice with spin-orbit coupling, identifying various topological insulator phases and their surface states through band structure and Z_2 indices analysis.

Contribution

It introduces a detailed phase diagram of topological insulators in an octahedron-decorated cubic lattice, revealing new strong and weak topological phases at specific fillings.

Findings

Identification of strong topological insulators at 1/6, 1/2, 2/3 fillings

Discovery of weak topological insulators at 1/6 and 2/3 fillings

Analysis of surface states characteristics

Abstract

We investigate a tight-binding model of the octahedron-decorated cubic lattice with spin-orbit coupling. We calculate the band structure of the lattice and evaluate the Z_2 topological indices. According to the Z_2 topological indices and the band structure, we present the phase diagrams of the lattice with different filling fractions. We find that the $(1;111)$ and $(1;000)$ strong topological insulators occur in some range of parameters at 1/6, 1/2 and 2/3 filling fractions. Additionally, the $(0;111)$ weak topological insulator is found at 1/6 and 2/3 filing fractions. We analyze and discuss the characteristics of these topological insulators and their surfaces states.