Optical studies of single-domain crystals of YBa2Cu3O6+x allow us to separate the CuO2-plane and CuO-chain contributions to the optical conductivity as a function of doping between 0.025 and 5.5 eV. We find several interesting consequences of doping on the optical conductivity of YBa2Cu3O6+x: the 4.1-eV transition in tetragonal YBa2Cu3O6.1 is split into a- and b-axis-polarized components by CuO-chain formation; oscillator strength associated with the charge-transfer band of insulating YBa2Cu3O6.1 is redistributed to low frequencies; and the low-frequency conductivity in the CuO2 planes evolves into a non-Drude response comprised of a single resolvable component. The CuO-chain conductivity, by contrast, is dominated by a midinfrared absorption band.
ASJC Scopus subject areas
- Condensed Matter Physics