2Cu 3O 7–δ near the Superconducting Transition Temperature]]>

摘要

Positive terahertz photoconductivity has been observed in underdoped high-temperature superconductors YBa~(2)Cu~(3)O~(7–δ)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.