6533b838fe1ef96bd12a4f00

RESEARCH PRODUCT

Charge transfer in high-Tc(Y/Pr)Ba2Cu3O7superlattices

subject

description

We comment on the charge-transfer model for the unique softening of the apex [O(4)] oxygen observed in Raman spectra of a- and c-oriented (${\mathrm{YBa}}_{2}$${\mathrm{Cu}}_{3}$${\mathrm{O}}_{7}$${)}_{\mathit{m}}$(${\mathrm{PrBa}}_{2}$${\mathrm{Cu}}_{3}$${\mathrm{O}}_{7}$${)}_{\mathit{n}}$ superlattices presented in a recent paper by Ham et al. [Phys. Rev. B 50, 16 598 (1994)]. We find the size of the charge transfer necessary for the observed shift too large to explain the observations. In addition, a conclusion about the unique behavior of both types of superlattices can only be drawn if the sample quality is properly considered. \textcopyright{} 1996 The American Physical Society.