Electrostatically defined serial triple quantum dot charged with few electrons

Max-Planck-Institut fu¨r Festk¨orperforschung, Heisenbergstrase 1, 70569 Stuttgart, Germany.(Dated: February 4, 2008)A serial triple quantum dot (TQD) electrostatically defined in a GaAs/AlGaAs heterostructure ischaracterized by using a nearby quantum point contact as charge detector. Ground state stabilitydiagrams demonstrate control in the regime of few electrons charging the TQD. An electrostaticmodel is developed to determine the ground state charge configurations of the TQD. Numericalcalculations are compared with experimental results. In addition, the tunnelingconductance throughall three quantum dots in series is studied. Quantum cellular automata processes are identified,which are where charge reconfiguration between two dots occurs in response to the addition of anelectron in the third dot.