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.