Topological Insulator in an Atomic Liquid

TL;DR

This paper theoretically demonstrates that an atomic liquid phase can support topologically nontrivial electronic structures, expanding the scope of topological materials to include liquids and amorphous systems.

Contribution

It introduces a two-orbital model for liquid topological insulators and shows how thermal fluctuations can preserve nontrivial topology in a liquid state.

Findings

Atoms crystallize into a topological lattice at high density

Thermal melting results in a liquid with inherited topological properties

Nonzero Bott index characterizes the liquid's topological nature

Abstract

We demonstrate theoretically an atomic liquid phase that supports topologically nontrivial electronic structure. A minimum two-orbital model of liquid topological insulator in two dimensions is constructed within the framework of tight-binding molecular dynamics. As temperature approaches zero, our simulations show that the atoms crystallize into a triangular lattice with nontrivial band topology at high densities. Thermal fluctuations at finite temperatures melt the lattice, giving rise to a liquid state which inherits the nontrivial topology from the crystalline phase. The electronic structure of the resultant atomic liquid is characterized by a nonzero Bott index. Our work broadens the notion of topological materials, and points to a new systematic approach for searching topological phases in amorphous and liquid systems.