We report the first tunneling measurements made on the new high-transition-temperature perovskite superconductors. These were obtained using an ultrahigh-vacuum low-temperature scanning-tunneling microscope. The superconducting gap of a La1.85Sr0.15CuO4-y sample is 123 mV, and the onset Tc is 40 K, from which 2/kBTc=72. The possibility that this surprisingly high ratio may be due to a mechanism other than superconductivity is discussed.
ASJC Scopus subject areas
- Condensed Matter Physics