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arXiv · 1407.2298

Nonlocal Andreev reflection, fractional charge and current-phase relation in topological bilayer exciton condensate junctions

M. Veldhorst·M. Hoek·M. Snelder·H. Hilgenkamp·A. A. Golubov·A. Brinkman
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Abstract

We study Andreev reflection and Josephson currents in topological bilayer exciton condensates (TEC). These systems can create 100% spin entangled nonlocal currents with high amplitudes due to perfect nonlocal Andreev reflection. This Andreev reflection process can be gate tuned from a regime of purely retro reflection to purely specular reflection. We have studied the bound states in TEC-TI-TEC Josephson junctions and find a gapless dispersion for perpendicular incidence. The presence of a sharp transition in the supercurrent-phase relationship when the system is in equilibrium is a signature of fractional charge, which can be further revealed in ac measurements faster than relaxation processes via Landau-Zener processes.

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M. Veldhorst, M. Hoek, M. Snelder, H. Hilgenkamp, A. A. Golubov, A. Brinkman. 2014-07-08. Nonlocal Andreev reflection, fractional charge and current-phase relation in topological bilayer exciton condensate junctions. https://doi.org/10.1103/physrevb.90.035428

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