Entanglement of nuclear spins in spin-blocked quantum dots

We theoretically study unique properties of nuclear spins in quantum dots: an entanglement derived by the spin flip of electrons through hyperfine interaction. The correlation among nuclear spins develops gradually in the presence of the electric current accompanied by the spin flip. This situation is relevant to a leakage current in spin-blocked regions where electrons cannot be transported unless their spins are flipped. The correlated state of nuclear spins drastically enhances the spin-flip rate of electrons and hence the leakage current. By numerical calculations, we show that the enhancement of the current is observable when the residence time of electrons in the quantum dots is shorter than the dephasing time View the MathML source of nuclear spins.