Line nodes in the energy gap of high-temperature superconducting BaFe_2(As_{1-x}P_x)_2 from penetration depth and thermal conductivity measurements

We report magnetic penetration depth and thermal conductiv ity data for high-quality single crystals of BaFe2(As1−xPx)2 (Tc = 30K) which provide strong evidence that this material has line nodes in its energy gap. This is distinctly different from the nodeless gap foun d for (Ba,K)Fe2As2 which has similarTc and phase diagram. Our results indicate that repulsive electronic in teractions play an essential role for Fe-based highTc superconductivity but that uniquely there are distinctly d ifferent pairing states, with and without nodes, which have comparable Tc.