Interfacial Line Energy of a Topological Phase

TL;DR

This paper investigates how topological fermions influence the interfacial line energy during phase transitions, revealing that topological boundary modes significantly alter nucleation processes and critical nucleus size.

Contribution

It introduces a minimal model coupling topological fermions to a scalar field, demonstrating quantum corrections to interface energy in topological phases.

Findings

Topological boundary modes increase the critical nucleus size.

Quantum corrections to interfacial line energy are characteristic of topological phases.

Coupling fermions to scalar fields alters nucleation and phase transition dynamics.

Abstract

In interacting topological systems, Landau-like order parameters interplay with the band topology of fermions. The physics of domain formation in such systems can get significantly altered due to the presence of topological fermions. In this work we show that coupling a topological fermionic field to a scalar field can drastically modify the nucleation processes. We find that existence of non-trivial fermionic boundary modes on the nucleating droplets of the scalar field leads to substantial quantum corrections to the interface energy. This leads to an increase in the size of the critical nucleus beyond which unrestricted droplet growth happens. To illustrate the phenomena we devise a minimal model of fermions in a Chern insulating system coupled to a classical Ising field in two spatial dimensions. Using a combination of analytic and numerical methods we conclusively demonstrate that topological phases have a characteristic quantum correction to the interfacial line energy. Apart from material systems, our work opens up a host of questions regarding the impact of fermionic topological terms on classical phase transitions and associated criticality.