Physical Review B

Edge-state-mediated collective charging effects in a gate-controlled quantum dot array

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We report the observation of two distinct types of magnetoconductance oscillations in six coupled quantum dots (QDs) in the integer quantum Hall regime. By tuning the magnetic field and gate voltage, we find robust conductance peaks and dips on the plateau of one conductance quantum 2e2/h. These features fall into two types associated with two different collective quantum states: for the first type, only dips and the crossing behaviors are found, and their traces show an anomalous temperature dependence, named "reversed Coulomb blockade oscillation", whereas for the second type, the peak traces show both crossing and anticrossing behaviors with resonance-type temperature dependence. Notably, all peaks show clear Coulomb diamonds in their differential conductance. We argue that the observed features reveal the electron addition spectra in an edge-state-mediated QD network, manifesting intricate interdot and dot-edge Coulomb interactions. In the first-type regime, the dots are more isolated from each other and the electron transport is governed by the dot-edge interaction. Conversely, in the second-type regime, the QDs behave as a coupled dot array due to the presence of strong interdot interactions. Our results open a route by using the edge-state-mediated multi-QD system as a laboratory for exploring coherent many-body interactions.