We have investigated the temperature variation of optical spectra comparatively for an oxygenated nonsuperconducting and a reduced superconducting crystal of Nd1.85Ce0.15Cu04+y. Anomalous gap-like structure as large as 0.3 eV has been observed in the optical conductivity spectrum of the oxygenated crystal with lowering temperature from 340 K, while little temperature-variation has been observed for the reduced crystal. Furthermore, anomalies in lattice dynamics have been observed only for the oxygenated crystal in far-infrared spectra. These spectral signatures have shown parallel temperature-dependence, signaling a possible charge ordering in the oxygenated nonsuperconducting crystal.
ASJC Scopus subject areas
- Atomic and Molecular Physics, and Optics
- Materials Science(all)
- Condensed Matter Physics