Fermi surface of superconducting LaFePO determined by quantum   oscillations
  We report extensive measurements of quantum oscillations in the normal state of the Fe-based superconductor LaFePO, (Tc ~ 6 K) using low temperature torque magnetometry and transport in high static magnetic fields (45 T). We find that the Fermi surface is in broad agreement with the band-structure calculations with the quasiparticle mass enhanced by a factor ~2. The quasi-two dimensional Fermi surface consist of nearly-nested electron and hole pockets, suggesting proximity to a spin/charge density wave instability. 
A.I. Coldea, J.D. Fletcher, A. Carrington, J.G. Analytis, A.F.   Bangura, J.-H. Chu, A.S. Erickson, I.R. Fisher, N.E. Hussey...