CONDUCTANCE PEAK SPLITTING IN CHARGE POLARIZED COUPLED QUANTUM DOTS

We report a measurement of linear conductance through a series double dot as a function of the total double dot charge and the charge differ ence for interdot tunnel conductances between zero and one mode. The d ots are defined by ten independently tunable electrostatic gates on th e surface of a GaAs/AlGaAs heterostructure to allow separate adjustmen t of dot charge and interdot conductance. For weak interdot tunneling the measured double dot conductance agrees with a transport model in w hich each dot is individually governed by Coulomb blockade theory. As interdot tunnel conductance increases toward one mode, the measured co nductance peak positions and shapes indicate both a relaxation of the charge quantization condition for individual dots and quantum mechanic al charge sharing between dots. The results are in quantitative agreem ent with many body charge fluctuation theory. (C) 1996 Academic Press Limited