Electronic correlations in the superconductor LaFeAsO0.89F0.11 with low carrier density

The crystal structure and numerous normal and superconducting state properties of layered tetragonal (P4/nmm) LaFeAsO, with F doping of approximate to 11%, are reported. Resistivity measurements give an onset transition temperature T-c=28.2 K, and low field magnetic susceptibility data indicate bulk superconductivity. In applied magnetic field, analysis of the resistive transition results in a critical field H-c2 approximate to 30 T and a coherence length xi(GL) approximate to 35 angstrom. An upper limit for the electron carrier concentration of 1 X 10(21) cm(-3) is inferred from the Hall data just above T-c. Strong electron-electron correlations are suggested from temperature-dependent resistivity, Seebeck coefficient, and thermal conductivity data. Anomalies near T-c are observed in both Seebeck coefficient and thermal conductivity data.