  We have studied the three-dimensional shapes of the Fermi surfaces (FSs) of
BaFe2(As1-xPx)2 (x=0.38), where superconductivity is induced by isovalent P
substitution, by angle-resolved photoemission spectroscopy. Moderately strong
electron mass enhancement has been identified for both the electron and hole
FSs. Among two observed hole FSs, the nearly two-dimensional one shows good
nesting with the outer two-dimensional electron FS, but its orbital character
is different from the outer electron FS. The three-dimensional hole FS shows
poor nesting with the electron FSs. The present results suggest that the
three-dimensionality and the difference in the orbital character weaken FS
nesting, leaving partial nesting among the outer electron FSs of dxy character
and/or that within the three-dimensional hole FS, which may lead to the nodal
superconductivity.
