Abstract
We report on far infrared measurements of the energy gap of the high-temperature superconductor . From the reflectance, measured over a wide range of frequencies, we calculate the optical conductivity. It shows phononlike lines at 239, 355, and 494 and a gaplike depression below 140 . The strong edge seen in reflectance at 50 , and misidentified by a number of investigators as the energy gap, does not appear in the conductivity. It is due to a zero crossing of (ω) caused by the strong phonons.
- Received 9 April 1987
DOI:https://doi.org/10.1103/PhysRevB.35.8843
©1987 American Physical Society