Electronic correlations in the superconductor La Fe As O 0.89 F 0.11 with low carrier density

摘要: The crystal structure and numerous normal superconducting state properties of layered tetragonal $(P4∕nmm)$ LaFeAsO, with F doping $\ensuremath{\approx}11%$, are reported. Resistivity measurements give an onset transition temperature ${T}_{c}=28.2\phantom{\rule{0.3em}{0ex}}\mathrm{K}$, low field magnetic susceptibility data indicate bulk superconductivity. In applied field, analysis the resistive results in a critical ${H}_{c2}\ensuremath{\approx}30\phantom{\rule{0.3em}{0ex}}\mathrm{T}$ coherence length ${\ensuremath{\xi}}_{\mathrm{GL}}\ensuremath{\approx}35\phantom{\rule{0.3em}{0ex}}\mathrm{\AA{}}$. An upper limit for electron carrier concentration $1\ifmmode\times\else\texttimes\fi{}{10}^{21}\phantom{\rule{0.3em}{0ex}}{\mathrm{cm}}^{\ensuremath{-}3}$ is inferred from Hall just above ${T}_{c}$. Strong electron-electron correlations suggested temperature-dependent resistivity, Seebeck coefficient, thermal conductivity data. Anomalies near ${T}_{c}$ observed both coefficient