Thermoelectric performance of topological boundary modes

TL;DR

This paper explores the thermoelectric properties of topological edge states in a finite-size Su-Schrieffer-Heeger model, demonstrating their potential for robust thermal device applications and non-equilibrium state preparation.

Contribution

It introduces a method to detect topological phases via transport observables and shows how to utilize edge states for efficient thermoelectric devices without asymmetric couplings.

Findings

Edge states can be detected through energy-resolved transmission, current, and noise.

Edge states can be prepared as stationary states in non-equilibrium conditions.

Topological devices outperform single quantum dot thermoelectric efficiency.

Abstract

We investigate quantum transport and thermoelectrical properties of a finite-size Su-Schrieffer-Heeger model, a paradigmatic model for a one-dimensional topological insulator, which displays topologically protected edge states. By coupling the model to two fermionic reservoirs at its ends, we can explore the non-equilibrium dynamics of the system. Investigating the energy-resolved transmission, the current and the noise, we find that these observables can be used to detect the topologically non-trivial phase. With specific parameters and asymmetric reservoir coupling strengths, we show that we can dissipatively prepare the edge states as stationary states of a non-equilibrium configuration. In addition, we point out that the edge states can be exploited to design a refrigerator driven by chemical work or a heat engine driven by a thermal gradient, respectively. These thermal devices do not require asymmetric couplings and are topologically protected against symmetry-preserving perturbations. Their maximum efficiencies significantly exceed that of a single quantum dot device at comparable coupling strengths.