Carrier dynamics and infrared-active phonons in c-axis oriented RuSr$_2$GdCu$_2$O$_8$ film

摘要

The conductivity spectra of c-axis oriented thin RuSr$_2$GdCu$_2$O$_8$ filmon SrTiO$_3$ substrate, prepared by pulsed-laser deposition, are obtained fromthe analysis of the reflectivity spectra over broad frequency range andtemperatures between 10 and 300 K. The free charge carriers are found to bestrongly overdamped with their scattering rate (1.0 eV at room temperature)exceeding the plasma frequency (0.55 eV). Four phonon lines are identified inthe experimental spectra and assigned to the specific oxygen related in-planepolarized vibrations based on the comparison with the results of a latticedynamics shell model calculations.