EDSR spectroscopy of the spin resonance frequency as a function of interdot detuning for each pair of neighbouring dots. The spins in quantum dots 1 and 2 are initialized in an anti-parallel state, after which the single spin from dot 2 is shuttled in bucket-brigade mode to the respective dot pair, a microwave burst is applied at a given interdot detuning and the spin is read out after shuttling back to dot 2. The colour scale shows the parallel spin probability, which here is a measure of the spin-flip probability, as a function of the applied frequency and interdot detuning. The inset depicts bucket-brigade mode tunnelling, transferring a single electron between dots.
