Decoupling the superconducting condensate from phonons in the far-infrared spectra of YBa{sub 2}Cu{sub 3}O{sub 7{minus}x}

摘要: The infrared reflection spectra of a YBa{sub 2}Cu{sub 3}O{sub 7{minus}{delta}} single crystal with large surface containing the c-axis have been recorded from 4 K to room temperature. Thermal treatment sample allowed them obtain for several {Tc}`s, ranging 50 91.3 on same sample. obtained results along show an extra band in superconducting phase which can be attributed formation Cooper pairs. By decoupling this absorption phonons and unpaired charge carriers, authors determined thermal evolution London penetration depth concentration pairs as function {Tc}. observed effects are compared BCS theory. 49 refs., 5 figs., 1 tab.