The anomalous effective surface Debye temperature of ErAs (100)

Abstract

We have investigated vibrational motions of the ErAs (100) surface, in the normal direction, by the low energy electron diffraction and X-ray photoemission spectroscopy. We have exploited the differences in electron mean free path, with changes in electron kinetic energies, to illuminate the dramatically lower effective Debye temperature of the surface. The effective surface Debye temperature, indicative of the dynamic motion of lattice normal to the surface, is 35±10 K. This is much smaller than the bulk Debye temperature of 353±63 K. The huge difference between the effective surface and bulk Debye temperatures, by far more than a factor of 2 , indicates that electronic structure of the surface is different from that of bulk.