Anomalous thermoelectric transport of Dirac particles in graphene

TL;DR

This study investigates the unique thermoelectric properties of graphene, revealing divergence in the Seebeck coefficient, a large Nernst signal at the Dirac point, and oscillatory behavior, highlighting graphene's potential for sensitive impurity detection.

Contribution

It provides the first detailed thermoelectric measurements of graphene under magnetic fields, demonstrating anomalous transport linked to its Dirac fermion nature.

Findings

Seebeck coefficient diverges as 1/n2D

Large Nernst signal (~50 μV/K at 8 T) at Dirac point

Oscillatory thermoelectric response at low temperatures

Abstract

We report a thermoelectric study of graphene in both zero and applied magnetic fields. As a direct consequence of the linear dispersion of massless particles, we find that the Seebeck coefficient Sxx diverges with 1 /, where n2D is the carrier density. We observe a very large Nernst signal Sxy (~ 50 uV/K at 8 T) at the Dirac point, and an oscillatory dependence of both Sxx and Sxy on n2D at low temperatures. Our results underscore the anomalous thermoelectric transport in graphene, which may be used as a highly sensitive probe for impurity bands near the Dirac point.