Long-range spin transfer in triple quantum dots.
Tunneling in a quantum coherent structure is not restricted to only nearest neighbors. Hopping between distant sites is possible via the virtual occupation of otherwise avoided intermediate states. Here we report the observation of long-range transitions in the transport through three quantum dots coupled in series. A single electron is delocalized between the left and right quantum dots, while the center one remains always empty. Superpositions are formed, and both charge and spin are exchanged between the outermost dots. The delocalized electron acts as a quantum bus transferring the spin state from one end to the other. Spin selection is enabled by spin correlations. The process is detected via the observation of narrow resonances which are insensitive to Pauli spin blockade.
Instituto de Ciencia de Materiales de Madrid, CSIC, Cantoblanco, 28049 Madrid, Spain.
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R
Sánchez
National Research Council Canada, 1200 Montreal Road, Ottawa, Ontario K1A 0R6, Canada.
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G
Granger
National Research Council Canada, 1200 Montreal Road, Ottawa, Ontario K1A 0R6, Canada and Département de physique, Université de Sherbrooke, Sherbrooke, Quebec J1K 2R1, Canada.
L
L
Gaudreau
National Research Council Canada, 1200 Montreal Road, Ottawa, Ontario K1A 0R6, Canada.
A
A
Kam
Département de physique, Université de Sherbrooke, Sherbrooke, Quebec J1K 2R1, Canada.
M
M
Pioro-Ladrière
National Research Council Canada, 1200 Montreal Road, Ottawa, Ontario K1A 0R6, Canada.
S A
SA
Studenikin
National Research Council Canada, 1200 Montreal Road, Ottawa, Ontario K1A 0R6, Canada.
P
P
Zawadzki
National Research Council Canada, 1200 Montreal Road, Ottawa, Ontario K1A 0R6, Canada.
A S
AS
Sachrajda
Instituto de Ciencia de Materiales de Madrid, CSIC, Cantoblanco, 28049 Madrid, Spain.
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G
Platero