Spiky density of states in large complex Al-Mn phases

First-principle electronic structure calculations have been performed in crystalline complex phases mu-Al4.12Mn and lambda-Al4.6Mn using the TB-LMTO method. The atomic structures contain about 560 atoms in a large hexagonal unit cell. One of the main characteristic of their density of states is the presence of fine peaks the so-called "spiky structure". From multiple-scattering calculations in real space, we show that these fine peaks are not artifacts in ab-initio calculations, since they result from a specific localization of electrons by atomic clusters of different length scales.