Polarized reflectance spectra of a (001) surface of YBa2Cu3O7 before and after detwinning

Autor: Hans Peter Geserich, A. Zibold, M. Dürrler, A. Erb, German Müller-Vogt
Rok vydání: 1990
Předmět:
Zdroj: Physica C: Superconductivity. 171:151-155
ISSN: 0921-4534
DOI: 10.1016/0921-4534(90)90468-t
Popis: We have performed reflection measurements on a (001) surface of a YBa 2 Cu 3 O 7 single crystal, using polarized light in the energy range between 50 meV and 6 eV. The crystal was grown with the typical twinned structure of this compound, showing a reflectance spectrum which was independent of the direction of polarization. The spectrum was characterized by free carrier absorption with a plasma edge near 1 eV. By applying uniaxial stress at 450°C the twinned structure was removed. The crystal surface was transformed into a single untwinned domain, resulting in a strong splitting of the plasma edge with respect to the direction of polarization. By fitting a Lorentz-Drude model to the polarized reflectance spectra of the single domain crystal, R ∥ a and R ∥ b , the tensor components of the dielectric function could be determined whereas the reflectance spectrum of the twinned surface represents an average of the components of both crystallographic directions.
Databáze: OpenAIRE