The measured energy spectra that probe the positions of the S–T − anticrossings as a function of the detuning ( ε i j ) and the barrier gate voltage (v b i j ) for the vertical DQDs 3–7 at B = 5 mT. The colour scale shows the measured spin triplet probability P T after initializing a vertical DQD in a singlet state (in (0,2) or (2,0)) and applying a gate voltage pulse (20 ns ramp in, 50 or 60 ns wait time, 0 ns ramp out to the PSB regime for readout) to the detuning shown on the horizontal axis, for different v b i j . The 20 ns ramp-in time is used to ensure adiabaticity with respect to the tunnel coupling (2 GHz), while maintaining diabaticity relative to the S–T − anticrossing. The wait time is close to a π rotation to obtain a sizable triplet probability. The cartoons on top of the panels f – i represent the eight dots, and the dark grey line indicates which exchange coupling is active in the panel below.
