DIPOLON-PLASMON INTERACTION IN HIGH-T-C SUPERCONDUCTING MATERIALS

In this article interaction between the dipolon waves and the longitud inal plasma waves has been studied adopting a self-consistent field ap proach. The combined dispersion relation has been obtained which shows that both the dipolon waves and the plasma waves are modified. We dis cuss our results in relevance to free-electron plasma peaks observed a t similar to 1.1 eV in inelastic electron scattering and optical spect roscopy measurements in high-temperature superconductors, Our calculat ions for YBa2Cu3O7 show that the plasma frequency decreases a whereas the slope of the plasmon dispersion curve at long wavelength increases because of interaction with dipolon excitations, consistent with the experimental result due to Romberg et al. Our investigation has made i t possible to propose that the experimentally observed peak at similar to 1.1 eV may be due to plasmons interacting with dipolon excitations in high-temperature superconductors.