Polarons and Bipolarons in Oxides

摘要

The possible role of large polarons and bipolarons in high-T_c cuprate superconductors and other oxides is analysed in the lgiht of experiments on their optical absorption spectra and taking into account several theoretical models. It is emphasized that the band mass of the carriers and therefore also the polaron coupling constant, key ingredients in any continuum polaron theory, are not known for most (if not all) of those oxides.