English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Plus monthly

Global: Zendy Tools annual

Global: Zendy Tools monthly

Global: Zendy Free Plan

The complex conductivity of YBa$_2$Cu$_3$O$_{7-\delta}$ samples representingthe optimally doped, the underdoped and the overdoped stoichiometry wasmeasured using time-domain terahertz spectroscopy. In the normal state, thefrequency dependence is described by the Drude model. Below the criticaltemperature $T_\mathrm{c}$, the two-fluid model was successfully employed tofit all the spectra, from 5 K up to $T_\mathrm{c}$. The temperature behaviourof fundamental parameters such as the scattering time $\tau$, the superfluidfraction $f_\mathrm{s}$ and the conductivity $\sigma$ was investigated at givenfrequencies. The real part of the conductivity $\sigma_1(T)$ exhibits acoherence-like peak at low frequencies, which slightly shifts with increasingfrequency whereas its height decreases. It can be observed for all threestoichiometries and its exact shape depends on the quality of the sample. Afurther analysis shows that this peak is a consequence of the competitionbetween the scattering time $\tau(T)$ and the superfluid fraction$f_\mathrm{s}(T)$. The decrease of the superfluid fraction towards$T_\mathrm{c}$ depends on the reduced temperature with a power law close to 2,suggesting a dirty d-wave superconductor case for all levels of doping.

Two-fluid model analysis of the terahertz conductivity of YBaCuO samples: optimally doped, underdoped and overdoped cases