Effect of Fermi Surface Topology on Inter-Layer Magnetoresistance in Layered Multiband Systems: Application to LaFeAsO1-xFx

In layered single band systems, the interlayer conductivity depends on the orientation of the in-plane magnetic field and takes maximum values when the magnetic field is perpendicular to flat regions of the Fermi surface. Extending this known results to multi-band systems, we propose an experiment to extract information about their Fermi surface topology. We discuss application of the formula to a FeAs-based superconductor, LaFeAsO$_{1-x}$F$_x$. We show that the magnetically ordered state in the parent compound is clearly distinguished from the paramagnetic state by the oscillation period in the interlayer conductivity. We demonstrate that evolution of the Fermi surface topology by changing the doping concentration is reflected to the interlayer conductivity oscillation patterns.Comment: 12 pages, 6 figures, corrected Fig.6, added clarifications and refs, to appear in J. Phys. Soc. Jp