Evolution of Coulomb blockade spectra in parallel coupled quantum dots

Abstract
We report low-temperature conductance measurements in the Coulomb blockade regime on two nominally identical tunnel-coupled quantum dots in parallel defined electrostatically in the two-dimensional gas of a GaAs/AlGaAs heterostructure. We find that the Coulomb blockade spectra of such devices exhibit two distinct sets of peaks, each of which behaves differently with varying interdot tunnel conductance and with temperature. The results conform to recent theories regarding the role of interdot quantum charge fluctuations, and provide evidence for the possible role of inelastic cotunneling between dots at finite interdot conductances.