Thermopower of Quantum Hall States in Corbino Geometry as a Measure of Quasiparticle Entropy

TL;DR

This paper demonstrates that thermopower measurements in a Corbino geometry provide a direct way to quantify quasiparticle entropy and quantum dimensions in quantum Hall states, especially non-Abelian ones.

Contribution

It establishes a theoretical relation between thermopower and quasiparticle entropy in Corbino geometry, highlighting its advantages over Hall bar measurements and extending to non-Abelian states.

Findings

Thermopower in Corbino geometry measures quasiparticle entropy per charge.

The relation holds for integer quantum Hall states at low temperatures.

Corbino thermopower can determine the quantum dimension of non-Abelian quasiparticles.

Abstract

Using the Onsager relation between electric and heat transport coefficients, and considering the very different roles played by the quantum Hall condensate and quasiparticles in transport, we argue that near the center of a quantum Hall plateau thermopower in a Corbino geometry measures {\it "entropy per quasiparticle per quasiparticle charge"}. This relation indicates that thermopower measurement in a Corbino setup is a more direct measure of quasiparticle entropy than in a Hall bar. Treating disorder within the self-consistent Born approximation, we show through an explicit microscopic calculation that this relation holds on an integer quantum Hall plateau at low temperatures. Applying this to non-Abelian quantum Hall states, we argue that Corbino thermopower at sufficiently low temperature becomes temperature-independent, and measures the quantum dimension of non-Abelian quasiparticles that determines the topological entropy they carry.