Single-Electron Charging Effects in a Semiconductor Quantum Wire with Side-Coupled Quantum Dot

We report on experimental studies of a quantum wire with side-coupled quantum dot defined by surface gate electrodes patterned on top of a GaAs/AlGaAs heterostructure. The dot is side-coupled to the wire by means of a split-gate electrode allowing for a control of coupling strength. Clear signatures of single-electron charging are observed in the low-temperature wire conductance within a broad range of tunnel couplings and wire widths. The oscillations in wire conductance associated with Coulomb peaks in the dot remain being visible for split-ate conductances exceeding G(0) = 2e(2)/h and for mean wire conductances of up to 2.5G(0). We explain this behavior as consequence of the two-dimensional sample geometry which can lead to asymmetric and effectively reduced coupling between the dot and the conducting modes in the wire and propose a modified sample layout that should be suitable to increase the coupling.