Superconducting energy gap and normal-state conductivity of a single-domain YBa2 Cu3 O7 crystal

作者：Z. Schlesinger, R. T. Collins, Frederic Holtzberg, Christopher Feild, S. H. Blanton, U. Welp, G. W. Crabtree, Yue‐Wen Fang, Jefferson Zhe Liu · 发表于：Physical Review Letters · 年份：1990 · DOI：10.1103/physrevlett.65.801 · 被引用次数：442 · 研究领域：Physics of Superconductivity and Magnetism、Advanced Condensed Matter Physics、Magnetic properties of thin films

Using polarized reflectivity measurements of single-domain crystals, we are able to distinguish chain and plane contributions to the infrared conductivity of ${\mathrm{YBa}}_{2}$${\mathrm{Cu}}_{3}$${\mathrm{O}}_{7}$. A substantial chain contribution to \ensuremath{\sigma}(\ensuremath{\omega}) persisting to low frequency and temperature is observed. For the intrinsic conductivity of the ${\mathrm{CuO}}_{2}$ planes a superconducting energy gap of 500 ${\mathrm{cm}}^{\mathrm{\ensuremath{-}}1}$ (2\ensuremath{\Delta}/${\mathit{kT}}_{\mathit{c}}$\ensuremath{\simeq}8) is evident in the infrared data, while the normal-state conductivity drops much more slowly with \ensuremath{\omega} than the ordinary Drude form, and can be described in terms of a scattering rate \ensuremath{\Elzxh}/${\mathrm{\ensuremath{\tau}}}^{\mathrm{*}}$\ensuremath{\sim}kT+\ensuremath{\Elzxh}\ensuremath{\omega} at low frequency. The former result (2\ensuremath{\Delta}/${\mathit{kT}}_{\mathit{c}}$\ensuremath{\simeq}8) suggests suppression of ${\mathit{T}}_{\mathit{c}}$; the latter, that ${\mathrm{YBa}}_{2}$${\mathrm{Cu}}_{3}$${\mathrm{O}}_{7}$ is not an ordinary Fermi liquid.