ISSN:
1572-9559
Source:
Springer Online Journal Archives 1860-2000
Topics:
Physics
Notes:
Abstract A thin film of NbN (thickness t = 300 Å), has been deposited on an MgO and a Si wafer. Both samples have been studied by transmission from 10 or 20 to 120 cm−1, and have exhibited one maximum of transmission at a given frequency like the classical superconductors as Pb, Sn or Hg in the superconductive state. From the Far IR experimental data, the characteristic temperature θc, and the gap frequency (νgap (θ) = 2 Δ (θ), Δ(θ) being the energy gap) are immediately obtained (for instance for the NbN / MgO sample, θc = 15.5 K; νg (5 K) = 39.7 cm−1), and it is seen that $$\frac{{{\text{2}}\vartriangle (4{\text{K)}}}}{{{\text{k}}_{\text{B}} \theta _c }} \approx 3.5$$ as expected from the BCS theory for a weak coupling. To fit the data we had to adjust only two additionnal parameters: collision and plasma frequency, νc (θ) and νp (including all carriers). At θ = 5 K, thebest fit for the NbN / MgO sample is obtained with νc = 371 cm−1 and νp = 12,600cm−1.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1023/A:1022616608395
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