Turning Zeeman splitting into switchable charge polarization in a double quantum dot

Abstract:A magnetic field that acts identically on two quantum dots is not expected to move charge between them. Nevertheless, we show that a uniform Zeeman field can strongly reconfigure and even reverse the single-electron charge polarization of an asymmetric open double quantum dot. Using a symmetry-preserving Green's-function equation-of-motion approach, we identify regimes where the preferred dot occupation reverses while the system remains in the single-electron charge sector. Two distinct mechanisms produce this behavior. Unequal gate levels produce different occupation responses because the Zeeman-shifted resonances lie at different positions relative to the reservoir chemical potential, whereas unequal onsite interactions distinguish the dots through their many-body addition spectra. Coulomb blockade stabilizes the single-electron sector, causing the reservoir-mediated response to appear as spatial charge redistribution rather than a change in total occupation. Our results establish a mechanism for magnetic control of charge polarization at fixed electrostatic detuning.

Mesoscale and Nanoscale Physics (cond-mat.mes-hall); Quantum Physics (quant-ph)

arXiv:2608.27625 [cond-mat.mes-hall]

(or arXiv:2608.27625v1 [cond-mat.mes-hall] for this version)

https://doi.org/10.48550/arXiv.2608.27625 Focus to learn more arXiv-issued DOI via DataCite (pending registration)

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