Electrical read-out of the local nuclear polarization in the quantum Hall effect

Abstract

It is demonstrated that the now well-established `flip-flop' mechanism of spin exchange between electrons and nuclei in the quantum Hall effect can be reversed. We use a sample geometry which utilizes separately contacted edge states to establish a local nuclear spin polarization --close to the maximum value achievable-- by driving a current between electron states of different spin orientation. When the externally applied current is switched off, the sample exhibits an output voltage of up to a few tenths of a meV, which decays with a time constant typical for the nuclear spin relaxation. The surprizing fact that a sample with a local nuclear spin polarization can act as a source of energy and that this energy is well above the nuclear Zeeman splitting is explained by a simple model which takes into account the effect of a local Overhauser shift on the edge state reconstruction.

arXiv commentSubmitted to Phys. Rev. Lett

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• Temperature-dependent dynamical nuclear polarization bistabilities in double quantum dots in the spin-blockade regime
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• Terahertz photoresponse of a quantum Hall edge-channel diode
• Classical information driven quantum dot thermal machines
• Ettingshausen Effect around Landau Level Filling Factor nu=3 Studied by Dynamic Nuclear Polarization
• Ground and Applied-Field-Driven Magnetic States of Antiferromagnets