Anisotropic thermal transport of 2D quasicrystals of decagonal Al-Ni-Co system

The anisotropic thermal conductivity of 2D quasicrystals of the decagonal Al-Ni-Co system has been measured over a wide range of temperature. The thermal conductivity value along the periodic axis shows the nearly same behavior as the dirty alloy system. The quasiperiodic thermal conductivity exhibits a typical plateau dependence similar to that of the disordered system. The anisotropic behavior of the measured thermal conductivity is discussed on the basis of phonon relaxation time approximation. The main contributions of phonon scattering processes in the periodic and quasiperiodic directions are phonon-electron interaction and point-defect-like scattering effect arising from Penrose tiling, respectively. A small increase above the plateau region in the quasiperiodic transport indicates hopping conduction of localized vibration modes assisted by phonons such as fracton excitations in the disordered system. (C) 1999 Elsevier Science B.V. All rights reserved.