Spin-state mixing in InAs double quantum dots

We quantify the contributions of hyperfine and spin-orbit-mediated singlet-triplet mixing in weakly coupled InAs quantum dots by electron transport spectroscopy in the Pauli spin-blockade regime. In contrast to double dots in GaAs, the spin-orbit coupling is found to be more than two orders of magnitudes larger than the hyperfine mixing energy. It is already effective at magnetic fields of a few mT, where deviations from pure hyperfine mixing are observed.