THE FLUCTUATION-INDUCED PSEUDOGAP IN THE OPTICAL CONDUCTIVITY OF HIGH-TEMPERATURE SUPERCONDUCTORS

The effect of fluctuations on ac conductivity of layered superconducto rs both for c-axis and ab-plane electromagnetic wave polarizations is shown. The fluctuation contributions to conductivity (paraconductivity , Maki-Thompson anomalous contribution, one-electron density of states renormalization) have different physical nature and signs and are fou nd to be suppressed by the external field for different characteristic frequencies. As a result the nonmonotonic frequency dependence (pseud ogap) in the infrared optical conductivity of HTS film is predicted. T he effect has to be especially pronounced in c-axis conductivity.