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 on GaAs/AlGaAs heterostructures at sub-Kelvin temperatures and zero magnetic field. Unlike conventional non-magnetic high-mobility 2D systems, the thermopower in our devices increases with decreasing temperature below 0.3 K, reaching values in excess of 100 $\mu$V/K, thus exceeding the free electron estimate by more than two orders of magnitude. With support from a parallel independent 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.

(to appear in Phys. Rev. Lett.)

References in corpus (4)

• Thermopower of a Kondo-correlated quantum dot
• Magnetotransport in disordered delta-doped heterostructures
• Magnetic field induced Coulomb blockade in small disordered delta-doped heterostructures
• Spin polarization in modulation-doped GaAs quantum wires

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