Debye temperature of the 10-fold d-Al-Ni-Co quasicrystal surface

The surface Debye temperature of the 10-fold surface of the decagonal d-Al-Ni-Co quasicrystal was determined by measuring the decay of low-energy electron diffraction intensities with temperature. The surface Debye temperatures obtained from the logarithmic dependence of the Debye-Waller attenuation were 416 +/- 40 K for an incident beam energy of 42 eV, and 485 +/- 50 K for an incident beam energy of 67 eV. The values measured at the lowest energy are lower than measurements of the bulk value, by approximately 25%. The variation with beam energy is attributed to the penetration depth of the electrons, with the Debye temperature rapidly approaching the bulk value for a penetration of just a few layers. Although this is similar to the typical behavior observed in periodic crystals, it differs from the behavior observed in earlier studies of icosahedral quasicrystals. (c) 2008 Elsevier B.V. All rights reserved.