Giant Nernst effect in a Kondo lattice close to a quantum critical point

TL;DR

This paper reports a giant Nernst effect in the heavy-fermion superconductor CeCoIn$_{5}$ near a quantum critical point, revealing a novel source of transverse thermoelectricity in strongly correlated electron systems.

Contribution

It uncovers an unexpectedly large Nernst signal in CeCoIn$_{5}$, indicating a new mechanism of thermoelectricity in heavy-fermion materials close to quantum criticality.

Findings

Giant Nernst signal emerges below 18 K

Signal exceeds expectations for multi-band Fermi-liquid metals

Unusual dominance over vortex-related signals in the mixed state

Abstract

We present a study of Nernst and Seebeck coefficients of the heavy-fermion superconductor CeCoIn$_{5}$. Below 18 K, concomitant with a field-dependent Seebeck coefficient, a large sub-linear Nernst signal emerges with a magnitude drastically exceeding what is expected for a multi-band Fermi-liquid metal. In the mixed state, in contrast with all other superconductors studied before, this signal overwhelms the one associated with the motion of superconducting vortices. The results point to a hitherto unknown source of transverse thermoelectricity in strongly interacting electrons.