Valence and Core-Level Photoelectron Spectroscopy Study of the Electronic Structure of Ni2P(0001)

The electronic structure of Ni2P( 0001) has been investigated by photoelectron spectroscopy utilizing synchrotron radiation. In the valence band spectra, a Ni 3d-P 3p hybrid band ( main band) and a satellite were observed at 0-4 eV and at 8 eV, respectively. The satellite showed a resonant behavior around the Ni 3p threshold, and is associated with the photoemission leading to the two-hole bound final state. From the analysis of the anti-resonance dip of the main band intensity, the Ni 3d component was proved to be included in the whole binding energy region of the main band. In the P 2p core-level spectra, the surface-shifted 2p levels were resolved from the bulk 2p levels, while the surface-shifted peaks were not found in Ni 3p spectra. The binding energies of the surface-shifted P 2p levels were lower than those of the bulk components by similar to 1 eV. The surface-shifted levels were attributed to the 2p levels of the surface P atoms which take on a six-fold coordination.