Interaction of axial infrared-active phonons with electronic excitations and phonon-mediated charge transfer in YBa2Cu3O7−x

✍ Scribed by V.M. Burlakov; K.F. Renk; A. Gaymann; J. Münzel; H.P. Geserich

• Publisher: Elsevier Science
• Year: 1994
• Tongue: English
• Weight: 589 KB
• Volume: 221
• Category: Article
• ISSN: 0921-4534
• DOI: 10.1016/0921-4534(94)90232-1

✦ Synopsis

We report on an infrared study of the resonance interaction between phonons and electronic excitations in an YBa2Cu307 single crystal. Our results show that two transverse axial phonon modes (to= 300 cm-t and to-~ 550 cm -1 ) are strongly coupled to the c-polarized electronic continuum resulting in Fano-type line shapes at temperatures below To. The calculated dimensionless coupling constants 2j of these modes are 0.3 and 0.45, respectively. The estimated value of the total coupling constant ). ~ 3 is high enough to account for the high Tc value. A dramatic increase in the bare oscillator strength of these phonons in the superconducting phase of YBa2Cu307 is interpreted in terms of phonon-mediated charge transfer between CuO2 plane and CuO chain through the BaO plane.