Tunable negative differential resistance controlled by spin blockade in single-electron transistors

The single-electron transistors containing a few electrons and spin polarized source and drain contacts were formed in GaAs/GaAlAs heterojunctions using metallic gates. Coulomb blockade measurements reveal well-defined regimes where a decrease in the current is observed with increasing bias. We establish that the origin of the negative regime is the spin-polarized detection of electrons combined with a long spin relaxation time in the dot.