Thermoelectric effect in high mobility single layer epitaxial graphene

TL;DR

This study investigates the thermoelectric response of high mobility epitaxial graphene on silicon carbide, revealing deviations from classical models and intrinsic suppression of thermopower in the quantum Hall regime.

Contribution

It provides new insights into the thermoelectric behavior of epitaxial graphene, highlighting deviations from the Mott relation and intrinsic thermopower suppression in the quantum Hall regime.

Findings

Deviation from Mott relation at high carrier density

Lower than predicted thermopower peaks in quantum Hall regime

Thermopower suppression is intrinsic to Dirac electrons

Abstract

The thermoelectric response of high mobility single layer epitaxial graphene on silicon carbide substrates as a function of temperature and magnetic field have been investigated. For the temperature dependence of the thermopower, a strong deviation from the Mott relation has been observed even when the carrier density is high, which reflects the importance of the screening effect. In the quantum Hall regime, the amplitude of the thermopower peaks is lower than a quantum value predicted by theories, despite the high mobility of the sample. A systematic reduction of the amplitude with decreasing temperature suggests that the suppression of the thermopower is intrinsic to Dirac electrons in graphene.