Electronic structure of BaNi 2 P 2 observed by angle-resolved photoemission spectroscopy

We have performed an angle-resolved photoemission spectroscopy (ARPES) study of ${\mathrm{BaNi}}_{2}{P}_{2}$ that shows a superconducting transition at ${T}_{c}$ $\ensuremath{\sim}$ 2.5 K. We observed hole and electron Fermi surfaces (FSs) around the Brillouin zone center and corner, respectively, and the shapes of the hole FSs dramatically changed with photon energy, indicating strong three dimensionality. The observed FSs are consistent with band-structure calculations and de Haas-van Alphen measurements. The mass enhancement factors estimated in the normal state were ${m}^{*}$/${m}_{b}$ $\ensuremath{\le}$ 2, indicating weak electron correlation compared to typical iron-pnictide superconductors. An electronlike Fermi surface around the $Z$ point was observed in contrast with BaNi${}_{2}$As${}_{2}$ and may be related to the higher ${T}_{c}$ of ${\mathrm{BaNi}}_{2}{P}_{2}$.