Electronic structure of Al-Cu-Fe quasicrystals

Abstract

The electronic structure of the Al-Cu-Fe quasicrystal is calculated by the TB-LMTO-ASA method in reciprocal space. The atomic structure of the quasicrystal is modeled by three approximants with 8, 16, and 40 atoms per unit cell. The following characteristics are calculated: partial densities of states for all components of the alloy, total density of states, and charge redistribution between the alloy components. The calculated densities of states are compared with the experimental data obtained by X-ray photoelectron spectroscopy. Good agreement between the experimental spectrum and the theoretical density of states curve is observed for the approximant with 40 atoms per unit cell. In other cases, the agreement is much worse. The calculated data are used to interpret the fundamental features of the experimental spectrum. The results of calculations show that the charge is transferred from transition metal to aluminum atoms, giving rise to d states of aluminum in the occupied part of the band.