Thermoelectric effect in high mobility single layer epitaxial graphene

摘要

The thermoelectric response of high mobility single layer epitaxial grapheneon silicon carbide substrates as a function of temperature and magnetic fieldhave been investigated. For the temperature dependence of the thermopower, astrong deviation from the Mott relation has been observed even when the carrierdensity is high, which reflects the importance of the screening effect. In thequantum Hall regime, the amplitude of the thermopower peaks is lower than aquantum value predicted by theories, despite the high mobility of the sample. Asystematic reduction of the amplitude with decreasing temperature suggests thatthe suppression of the thermopower is intrinsic to Dirac electrons in graphene.