Abstract
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 language | English |
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Pages (from-to) | 1525-1528 |
Number of pages | 4 |
Journal | Physical review letters |
Volume | 76 |
Issue number | 9 |
DOIs | |
Publication status | Published - 1996 |
All Science Journal Classification (ASJC) codes
- Physics and Astronomy(all)