title: Highly enhanced thermopower in two-dimensional electron systems at millikelvin temperatures.
abstract: We report experimental observation of an unexpectedly large thermopower in mesoscopic two-dimensional (2D) electron systems in GaAs/AlGaAs heterostructures at sub-Kelvin temperatures and zero magnetic field. Unlike conventional nonmagnetic high-mobility 2D systems, the thermopower in our devices increases with decreasing temperature below 0.3 K, reaching values in excess of 100 microV/K, thus exceeding the free electron estimate by more than 2 orders of magnitude. With support from a parallel study of the local density of states, we suggest such a phenomenon to be linked to intrinsic localized states and many-body spin correlations in the system.
authors: Cavendish Laboratory, University of Cambridge, J.J. Thomson Avenue, Cambridge CB3 0HE, United Kingdom. sg483@cam.ac.uk
authors: Srijit
authors: S
authors: Goswami
authors: Christoph
authors: C
authors: Siegert
authors: Matthias
authors: M
authors: Baenninger
authors: Michael
authors: M
authors: Pepper
authors: Ian
authors: I
authors: Farrer
authors: David A
authors: DA
authors: Ritchie
authors: Arindam
authors: A
authors: Ghosh