Disordered Superconducting thin films

STM image 400 nm x 400 nm. At low temperature (100mK), superconducting areas (yellow) and normal areas (orange) spontaneously appear on disordered TiN thin films.


In highly disordered thin films of TiN , we have measured spatial fluctuations of the superconductivity. Unexpectedly, only two types of areas have been observed : either fully superconducting areas with a BCS gap in agreement with the bulk critical temperature or normal areas displaying either a flat density of states around the Fermi level or a zero bias anomaly related to Coulomb interactions. Moreover, the evolution of this density of states between these two zones reflects an anomalous proximity effect [1].


[1] Anomalous proximity effect in an Inhomogeneous Disordered Superconductor W. Escoffier, C. Chapelier, N. Hadacek, and J.-C. Villégier
Phys. Rev. Lett. 93, 217005 (2004).

 

Spatial evolution of the tunneling spectra between a superconducting area and a normal one along the blue line drawn on the STM picture.

Last update : 05/27 2009 (472)

 

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