Absence of strong correlation in Li ₂Pd ₃B

We use x-ray photoemission spectroscopy to study the electronic structure of new superconductor Li ₂Pd ₃B. Binding energies of the Pd 3p and 3d indicate valency that is intermediate between Pd metal (0±) and PdO(2+), or effectively Pd 4d ⁹ configuration. Comparison of satellite features in core level spectra of Li ₂Pd ₃B with that of PdO suggests that a larger hybridization strength of Li ₂Pd ₃B than that of PdO. The valence band spectrum is in excellent agreement with first principle band structure calculations, allowing us to ascribe the states at the Fermi level responsible for the superconductivity to be mainly Pd 4d hybridized with B 2p and Li 2p. These observations indicate that correlation effects play a negligible role for the physical properties of the new superconductor.