Fano effect in the a − b plane of Nd 1.96 Ce 0.04 CuO 4 + y : Evidence of phonon interaction with a polaronic background
Year: 1998
Type: article
Abstract: Reflectance measurements in different ${\mathrm{Nd}}_{1.96}{\mathrm{Ce}}_{0.04}{\mathrm{CuO}}_{4+y}$ samples with properly selected carrier concentrations provide firm evidence of Fano antiresonances for the four transverse optical ${E}_{u}$ phonons in the $a\ensuremath{-}b$ plane. An analysis of the Fano line shapes and of the dependence on temperature of the renormalized phonon frequencies allows us to determine the origin of the electronic continuum interacting with the phonons. Unlike in doped semiconductors, where the continuum is the free-carrier absorption band, here the continuum is provided by a polaron band at $\ensuremath{\sim}0.1\mathrm{eV},$ present in most parent compounds of high-${T}_{c}$ superconductors. In the most doped sample, the polaron band softens as $T$ decreases, thus indicating a delocalization of the polaronic carriers at low temperature.
Institution: Sapienza University of Rome
Language: English
Subfield: Condensed Matter Physics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W2000398222