Relaxation of exciton excitations in high-temperature superconductors

Exciton relaxation at free carriers is examined under the assumption that optical dd-transitions in high-temperature superconducting compounds correspond to the excitation of coupled states of holes and electrons (i.e., excitons). It is shown that the experimentally observed changes in the absorption (transmission) intensity with the excitation of excitons (initially, 3d9 - 3d9 transitions in Cu/2+/) may be related to a superconducting transition in a two-dimensional metallized free-carrier system.