Determination of the Debye Temperature of Ni(110) using the Inverse Photoemission technique.*

We have used k-resolved inverse photoemission spectroscopy to measure the temperature-dependent intensity of radiative transitions into the unoccupied electronic states of Ni(110) along the ΓY direction in the surface Brillouin zone. Our results indicate that the crystal-derived surface state acquires bulk-like characteristics near the projected bulk band boundary. The attenuation of the intensity of the transitions into the unoccupied bulk states with increasing temperature can be interpreted using the Debye-Waller factor. Using our results of transitions into the sp-derived bulk state observed at ∼1 eV above the Fermi level, we have determined that the Debye temperature of Ni(110) is 340 ± 20 K.