title: Exchange-Induced Spin Blockade in a Two-Electron Double Quantum Dot.
abstract: We have experimentally identified the exchange-induced spin blockade in a GaAs double quantum dot. The transport is suppressed only when the eigenstates are well-defined singlet and triplet states, and thus sensitive to dynamic nuclear-spin polarization that causes singlet-triplet mixing. This gives rise to unusual current spectra, such as a sharp current dip and an asymmetric current profile near the triplet resonance of a double quantum dot. Numerical simulations suggest that the current dip is a signature of identical nuclear-spin polarization in the two dots, which is attractive for coherent spin manipulations in a material with nuclear spins.
authors.affiliation: Department of Physics, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro 152-8551, Japan.
authors.forename: D
authors.initials: D
authors.lastname: Imanaka
authors.affiliation: Department of Physics, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro 152-8551, Japan.
authors.forename: S
authors.initials: S
authors.lastname: Sharmin
authors.affiliation: Department of Physics, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro 152-8551, Japan.
authors.forename: M
authors.initials: M
authors.lastname: Hashisaka
authors.affiliation: NTT Basic Research Laboratories, NTT Corporation, 3-1 Morinosato-Wakamiya, Atsugi 243-0198, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Muraki
authors.affiliation: Department of Physics, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro 152-8551, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Fujisawa