Grazing incidence infrared reflectivity of La1.85Sr0.15CuO4 and NbN

H. S. Somal, B. J. Feenstra, J. Schützmann, Jae Hoon Kim, Z. H. Barber, V. H.M. Duijn, N. T. Hien, A. A. Menovsky, Mario Palumbo, D. Van der Marel

Research output: Contribution to journalArticlepeer-review

44 Citations (Scopus)


Infrared reflectivity measurements, using p-polarized light at a grazing angle of incidence, show an increased sensitivity to the optical conductivity of highly reflecting superconducting materials. We demonstrate that when this measurement technique is applied to the conventional s-wave superconductor NbN, the results are in perfect agreement with BCS theory. For the in-plane response of a La1.85Sr0.15CuO4 single crystal, in the superconducting state, we find a reduction of the optical conductivity in the frequency range below 20 meV. The observed frequency dependence excludes an isotropic s-wave gap, but agrees well with model calculations assuming a d-wave order parameter.

Original languageEnglish
Pages (from-to)1525-1528
Number of pages4
JournalPhysical review letters
Issue number9
Publication statusPublished - 1996

All Science Journal Classification (ASJC) codes

  • Physics and Astronomy(all)


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