Features of the Terahertz Photoconductivity in YBa2Cu3O7–δ near the Superconducting Transition Temperature

Abstract

Positive terahertz photoconductivity has been observed in underdoped high-temperature superconductors YBa2Cu3O7-delta at temperatures somewhat higher than the midpoint of the superconducting transition. The amplitude of the effect is almost independent of the temperature and the power of the incident radiation if the latter exceeds a certain threshold value. The mechanisms responsible for the appearance of the effect are discussed.