Signatures of spin pairing in chaotic quantum dots.
Coulomb blockade resonances are measured in a GaAs quantum dot in which both shape deformations and interactions are small. The parametric evolution of the Coulomb blockade peaks shows a pronounced pair correlation in both position and amplitude, which is interpreted as spin pairing. As a consequence, the nearest-neighbor distribution of peak spacings can be well approximated by a modified bimodal Wigner surmise, in which interactions are taken into account beyond the constant interaction model.
Lüscher
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Solid State Physics Laboratory, ETH Zürich, Switzerland.
Heinzel
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Ensslin
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Wegscheider
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Bichler
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M