Anisotropic electronic Raman scattering in untwinnedYBa2Cu3O7−δ

Abstract

Raman scattering results from an untwinned domain of a pure-phase crystal of the $\mathrm{Y}{\mathrm{Ba}}_2{\mathrm{Cu}}_3{\mathrm{O}}_{7-\delta }$ superconductor are presented. The room-temperature spectrum in the polarization geometry parallel to the Cu(1)-O(1) chains shows significantly more spectral weight due to electronic scattering than does the spectrum in the perpendicular geometry. The anisotropy is further evidenced by the difference in antiresonance strength between the low-energy 116-${\mathrm{cm}}^{-1\mathrm{}}$ modes of these two geometries. Low-temperature spectra show similar anisotropy, suggesting that the Cu(1)-O(1) chains may contribute to this electronic scattering.