Electronic structure of the surface: Angle-resolved photoemission study

The electronic structure of Ni 2 P ( 10 1 ̄ 0 ) has been investigated by photoemission spectroscopy (PES) utilizing synchrotron radiation. The surface prepared by Ar + ion sputtering (3 kV, 15 min) and annealing (400 °C) gave a c(4 ×2) low-energy electron diffraction pattern. In the PES spectra measured for this surface, a Ni 3d–P 3p hybrid band (main band) and a satellite were observed at 0–4 eV and at 8 eV, respectively. Resonant PES study showed that the satellite is associated with the photoemission process leading to a two-hole bound state. The angle-resolved PES measurements showed that there were at least two surface states; one was observed at about 0.4 eV around the Γ ¯ point and the other was observed at about 0.6 eV along the boundary of the surface Brillouin zone along the [0001] direction.