Sequential and co-tunneling behavior in the temperature-dependent thermopower of few-electron quantum dots

R. Scheibner, E. G. Novik, T. Borzenko, M. Koenig, D. Reuter, A. D. Wieck, H. Buhmann, L. W. Molenkamp

Published 2006-08-08Version 1

We have studied the temperature dependent thermopower of gate-defined, lateral quantum dots in the Coulomb blockade regime using an electron heating technique. The line shape of the thermopower oscillations depends strongly on the contributing tunneling processes. Between 1.5 K and 40 mK a crossover from a pure sawtooth- to an intermitted sawtooth-like line shape is observed. The latter is attributed to the increasing dominance of cotunneling processes in the Coulomb blockade regime at low temperatures.