Temperature dependence of the diffusive thermopower in the two-dimensional interacting electron gas

¹ Centre d'Elaboration de Materiaux et d'Etudes Structurales (CNRS) and Université Paul Sabatier 29 Rue Jeanne Marvig, 31055 Toulouse, France, EU
² Institute of Solid State Physics RAS - Chernogolovka, Moscow District, 142432, Russia

^a gold@cemes.fr

Received: 11 July 2011
Accepted: 31 August 2011

Abstract

We evaluate the thermoelectric properties of the interacting two-dimensional electron gas in the presence of disorder at low temperatures. The diffusive (d) thermoelectric power (Seebeck coefficient) S_d (T) as function of the temperature T is calculated using the relaxation time approximation and we find S_d(T→0)/T=c₁+c₂T if short-range disorder is considered. The anomalous screening properties of the two-dimensional electron gas due to the Kohn anomaly, also responsible for Friedel oscillations, lead i) to a new contribution to c₁ depending on interaction effects and ii) to an anomalous temperature dependence of the thermopower. It is shown that at low density many-body effects due to exchange and correlation strongly modify the thermopower. Numerical results for Si-MOSFET structures are presented.