Regensburg 2010 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 7: SC: Heterostructures, Andreev Scattering, Proximity Effect, Coexistence

TT 7.10: Vortrag

Montag, 22. März 2010, 16:45–17:00, H20

Crossed Andreev Reflection and Charge Imbalance in Diffusive Normal-Superconducting-Normal Structures — •Dmitry Golubev¹, Mikhail Kalenkov², and Andrei Zaikin¹ — ¹Karlsruhe Institut für Technologie, Institut für Nanotechnologie, Karlsruhe, Germany — ²I.E. Tamm Department of Theoretical Physics, P.N. Lebedev Physics Institute, Moscow, Russia

We formulate a microscopic theory of non-local electron transport in three-terminal diffusive normal-superconducting-normal (NSN) structures with arbitrary interface transmissions. At low energies ε we predict strong enhancement of non-local spectral conductance g₁₂ ∝ 1/ε due to quantum interference of electrons in disordered N-terminals. In contrast, non-local resistance R₁₂ remains smooth at small ε and, furthermore, is found to depend neither on parameters of NS interfaces nor on those of N-terminals. At higher temperatures R₁₂ exhibits a peak caused by the trade-off between charge imbalance and Andreev reflection. Our results are in a good agreement with recent experimental observations and can be used for quantitative analysis of future experiments.