Determination of the surface Debye temperature of Mo(112) using valence band photoemission

The temperature dependence of the valence-band emission from the (112) surface of molybdenum has been studied with ultraviolet photoemission spectroscopy. Valence-band features arising from the bulk and surface states exhibit different temperature dependences. The results can be explained in terms of bulk and surface vibrational disorder. A surface (bulk) Debye temperature of 313 K (422 K) is extracted from the data. These numbers will be compared to surface Debye temperatures measured with different techniques and on other materials. The conclusion is that there are major inconsistencies in the reported ratio of the surface to bulk Debye temperature, presumably as a result of the approximations used to include thermal motion in the analysis.