Evidence of charge localization from photoinduced infrared absorption in BaBiO3

Photoinduced infrared activities were studied in BaBiO3 and the results compared with those of La2CuO4 with YBa2Cu3Osub(6+x). The spectral range of investigation covered the interval from 50 to 4000 cm-1. Clear evidence of lattice relaxation around the photoinjected charges was observed in the phonon spectral range with the bleaching of IR phonon bands. On the high energy side, the rising edge of a broad electronic absorption was observed. The results give an evidence of the suppression of the charge density wave due to the lattice relaxation around the photoinjected carriers. Morever the low-energy charge excitation in the near infrared appears as a commomn characteristic of both layered and three-dimensional high Tc superconductors, and may be relevant in the pairing mechanism. (author). 3 figs., 13 refs