Precise experimental characterization of a double quantum dot system with strong capacitive interdot coupling

We discuss the experimental determination of appropriate coordinate axes to measure energies in the honeycomb stability diagram of a new double quantum dot structure with strong capacitive interdot coupling. We show that a variation in the charging energies is due to an increase in dot-lead capacitances upon barrier opening, which must generally be taken into account in measurements at high tunnel coupling. In contrast, all other capacitances are constant in our structure.