Line nodes in the energy gap of superconducting BaFe2(As1-xPx)2 single crystals as seen via penetration depth and thermal conductivity

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