Far-infrared optical absorption and reflectivity of a superconducting NbN film

K. E. Kornelsen; M. Dressel; J. E. Eldridge; M. J. Brett; K. L. Westra

doi:10.1103/PhysRevB.44.11882

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Far-infrared optical absorption and reflectivity of a superconducting NbN film

K. E. Kornelsen, M. Dressel, J. E. Eldridge, M. J. Brett, K. L. Westra

DOI 10.1103/PhysRevB.44.11882 · Physical Review B

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Abstract

We report measurements of bolometric absorption and absolute reflectivity of a thin film of NbN on a silicon substrate, above and below the superconducting transition temperature of 13.3 K. The opening of the gap at an energy of 3.9 kBTc is seen clearly in both types of measurement. The data are compared with the predictions of the Mattis-Bardeen theory. The change in the reflectivity and the absorption at energies above 2Δ is larger than that calculated from the theory. By an analysis of the reflectivity data, it is shown that the theoretical values of the complex superconducting conductivity are too high.

Source-reported materials — not catalogue approval

Formula	Reported Tc (K)	Pressure (GPa)	Type
NbN Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	13.3	Pressure not reported	zero_resistance
(BEDT-TTF)2Cu(NCS)2 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	10	Pressure not reported	unknown