Photoinduced phase transition in YBa_2Cu_3O_x observed by in-situ Resonant Raman spectroscopy

摘要

Raman measurements in YBa_2Cu_3O_x (x = 6.35 - 6.82) with Ortho-II/III superstructural ordering reveal intense phonon scattering due to an electronic resonance localized near oxygen vacancies in the CuO-chains. Below room-temperature the resonance can be photo-bleached in a manner similar to reported persistent photo-induced superconductivity effects, indicating photon-assisted oxygen ordering. By comparing Raman and x-ray diffraction data we establish a correlation between the stability of the photo-induced state and the superstructure formation in the CuO-chains.