The Department of Physics Colloquium

 Series Presents

Maria Spies

Quasiparticle-based and Cooper pair-based superconducting diodes

Diodes are key elements for electronics, optics, and detection. Their evolution towards low dissipation electronics has lead to the hybridization with superconductors (S) and the realization of non-reciprocal transport of both quasiparticles and Cooper pairs. That occurs when both spatial inversion and time-reversal symmetries are broken.

Here, we review both effects comparing their efficiencies and basic principles.

The quasi-particle diode[1] is a superconducting tunnel junction with zero conductance in only one direction. The direction-selective propagation of the charge has been obtained through the broken electron-hole symmetry induced by the spin selection of a ferromagnetic tunnel barrier made of a EuS thin film separating a superconducting Al and a normal metal Cu layer. It achieves a large rectification of up to ∼40%.

[1] Strambini, E., Spies, M. et al. Nat Commun 13, 2431 (2022)