Jt. Devreese et J. Tempere, LARGE-POLARON EFFECTS IN THE INFRARED-SPECTRUM OF HIGH-T-C CUPRATE SUPERCONDUCTORS, Solid state communications, 106(5), 1998, pp. 309-313
The infrared absorption spectra of high-T-c cuprate superconductors ar
e examined in the framework of the theory for the optical absorption o
f single large polarons. The experimental so-called ''anomalous Drude'
' contribution to the optical absorption exhibits similarities, both i
n lineshape and in temperature dependence, to the low-frequency to (om
ega < omega(LO phonon)) theoretical large polaron absorption spectrum.
The polaron spectrum at omega > omega(LO phonon) has a similar temper
ature and frequency dependence as the experimentally observed absorpti
on band around 1000 cm(-1) (denoted as the ''d-band''). We present com
parisons between theory and experiment for specific cuprate materials,
namely Bi2Sr2CaCu2O8 and YBa2Cu3O7 using as input for the theoretical
calculations the experimental phonon frequencies together with a sing
le fitting material parameter. (C) 1998 Elsevier Science Ltd. All righ
ts reserved.