Andreev Billards

Scanning electron microscope image of an array of circular Andreev billiards (Au, diameter 200 nm surrounded by Nb)

We investigated the LDOS of artificially fabricated normal metal nano-structures (Au) in contact with a superconductor (Nb). Local spectroscopic measurements revealed the presence of well defined sub-gap peaks at various positions of the STM tip. The peak features suggest they originate from quasi-particle bound states within the normal-metal structures (De Gennes St James states). Refocusing of electronic trajectories induced by the granular structure of the samples can explain the observation of spatially uncorrelated interference effects in a non-ballistic medium[2].

[2] Ballistic effects in a proximity induced superconducting diffusive metal W. Escoffier, C. Chapelier, , F. Lefloch
To be published in Phys. Rev. B Rapid Com.


Localized bound states in the LDOS of a square Andreev billiard measured at 60 mK for different positions of the STM tip.

Last update : 05/27 2009 (473)


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