Superconducting energy gap and normal state conductivity of a single domain Y1Ba2Cu3O7 crystal.

摘要

Using polarized reflectivity measurements of single domain crystals, we are able to distinguish chain and plane contributions to the infrared conductivity of Y(sub 1)Ba(sub 2)Cu(sub 3)O(sub 7). A substantial chain contribution to (sigma)((omega)) persisting to low frequency and temperature is observed. For the intrinsic conductivity of the CuO(sub 2) planes a superconducting energy gap of 500 cm(sup (minus)1) (2(Delta)/k(Tc) (approx equal) 8) is evident in the infrared data, while the normal state conductivity drops much more slowly with (omega) than the ordinary Drude form, and can be described in terms of a scattering rate (Dirac h)/(tau)* (approximately) kT + (Dirac h)(omega) at low frequency. The former result (2(Delta)/k(Tc) (approx equal) 8) suggests substantial suppression of (Tc); the latter, that Y(sub 1)Ba(sub 2)Cu(sub 3)O(sub 7) is not ordinary Fermi liquid. 26 refs., 4 figs.