Effective surface Debye temperature for NiMnSb(100) epitaxial films

The surface Debye temperature of the NiMnSb (100) epitaxial films has been obtained using low energy electron diffraction, inverse photoemission, and core-level photoemission. The normal dynamic motion of the (100) surface re sults in a value for the effective surface Debye temperature of 145 +/- 13 K. This is far smaller than the bulk Debye temperature of 312 +/- 5 K obtai ned from wave vector dependent inelastic neutron scattering. The large diff erence between these measures of surface and bulk dynamic motion indicates a soft and compositionally different (100) surface. (C) 2000 American Insti tute of Physics. [S0003-6951(00)05127-5].