Determining gap nodal structures in Fe-based superconductors:   angle-dependence of the low temperature specific heat in an applied magnetic   field
  Since the discovery of high-Tc LaO_1-xF_xFeAs, and other such systems based on FeAs layers, several proposals have been made for the superconducting order parameter Delta_k, on both phenomenological and microscopic grounds. Here we discuss how the symmetry of Delta_k in the bulk can be determined, assuming that single crystals will soon be available. We suggest that a measurement of the dependence of the low temperature specific heat on the angle of a magnetic field in the FeAs plane is the simplest such method, and calculate representative specific heat vs. field angle oscillations for the various candidate states, using a phenomenological band structure fitted to the DFT Fermi surface. 
S. Graser, G.R. Boyd, Chao Cao, Hai-Ping Cheng, P.J. Hirschfeld, D.J.   Scalapino