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Singlet-Triplet Transition Tuned by Asymmetric Gate Voltages in a Quantum Ring

A. Fuhrer·T. Ihn·K. Ensslin·W. Wegscheider·M. Bichler
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Abstract

Wavefunction and interaction effects in the addition spectrum of a Coulomb blockaded many electron quantum ring are investigated as a function of asymmetrically applied gate voltages and magnetic field. Hartree and exchange contributions to the interaction are quantitatively evaluated at a crossing between states extended around the ring and states which are more localized in one arm of the ring. A gate tunable singlet-triplet transition of the two uppermost levels of this many electron ring is identified at zero magnetic field.

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A. Fuhrer, T. Ihn, K. Ensslin, W. Wegscheider, M. Bichler. 2003-06-26. Singlet-Triplet Transition Tuned by Asymmetric Gate Voltages in a Quantum Ring. https://doi.org/10.1103/physrevlett.91.206802

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