Measurement of magnetic penetration depth and superconducting energy gap in very thin epitaxial NbN films

Applied Physics Letters (Impact Factor: 3.52). 01/2010; 96. DOI: 10.1063/1.3314308
Source: arXiv

ABSTRACT We report the evolution of the magnetic penetration depth (lambda) and superconducting energy gap (Delta) in epitaxial NbN films with thickness (d) varying between 51-3 nm. With decrease in film thickness Tc and Delta(0) monotonically decreases, whereas lambda(0) monotonically increases. Our results show that while the values of Delta(0) and lambda(0) are well described by Bardeen-Cooper-Schrieffer theory, at elevated temperatures, films with d

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