Thermoelectric and Magnetothermoelectric Transport Measurements of Graphene

TL;DR

This paper reports simultaneous measurements of conductance and thermoelectric power in graphene, revealing sign changes, quantum Hall effects, and validation of the Mott relation with some deviations near charge neutrality.

Contribution

It provides comprehensive experimental data on graphene's thermoelectric and magnetothermoelectric transport, confirming theoretical relations and highlighting deviations at charge neutrality.

Findings

Sign change of TEP across charge neutrality point

Quantized thermopower and Nernst signals in quantum Hall regime

Agreement with Mott relation except near charge neutrality

Abstract

The conductance and thermoelectric power (TEP) of graphene is simultaneously measured using microfabricated heater and thermometer electrodes. The sign of the TEP changes across the charge neutrality point as the majority carrier density switches from electron to hole. The gate dependent conductance and TEP exhibit a quantitative agreement with the semiclassical Mott relation. In the quantum Hall regime at high magnetic field, quantized thermopower and Nernst signals are observed and are also in agreement with the generalized Mott relation, except for strong deviations near the charge neutrality point.