Cooperative Lifting of Spin Blockade in a Three-Terminal Triple Quantum Dot

We report measurements of multi-path transport through a triple quantum dot (TQD) in the few-electron regime using a GaAs three-terminal device with a separate lead attached to each dot. When two paths reside inside the transport window and are simultaneously spin-blockaded, the leak currents through both paths are significantly enhanced. We suggest that the transport processes in the two paths cooperate to lift the spin blockade. Fine structures in transport spectra indicate that different kinds of cooperative mechanisms are involved, depending on the details of the three-electron spin states governed by the size of exchange splitting relative to nuclear spin fluctuations. Our results indicate that a variety of correlation phenomena can be explored in three-terminal TQDs.