ARPES Study of Localized Charge Carriers in Y0.9Ca0.1Ba2Cu3O6.8 High-Temperature Superconductor

The connection between the peak of density of electronic states at similar to 0.4 eV below the Fermi level and the localization of charge carriers at compression of the height of CuO5 pyramids has been found by a comparison of experimental angle-resolved photoemission spectra data for Y0.9Ca0.1Ba2Cu3O6.8 single crystal and calculations of the electronic structure in a framework of the density functional theory. Both experiment and calculation are performed using 34.6 and 90.2 eV photon energy. The excitation energy does not have any noticeable influence on the peak of density of electronic states. Crystal structure distortions on the crystal surface result in observation of localized electronic states below the temperature of superconducting transition.

Automated summary

The connection between the density peak of electronic states and the localization of charge carriers at the compression of CuO5 pyramids in Y0.9Ca0.1Ba2Cu3O6.8 single crystal is found through a comparison of experimental angle-resolved photoemission spectra data and electronic structure calculations using density functional theory. Both experiment and calculation are performed using photon energies of 34.6 and 90.2 eV. Excitation energy does not affect the density peak of electronic states. Crystal structure distortions on the surface result in the observation of localized electronic states below the superconducting transition temperature.