Electronic structure of amorphousSi0.8Al0.2

Several random Bethe lattices capable of simulating the atomic structure of amorphous ${\mathrm{Si}}_{1\mathrm{-}\mathrm{x}}$ ${\mathrm{Al}}_{\mathrm{x}}$ are defined and the corresponding density of electronic states analyzed. It is shown that the electronic structure of the amorphous alloy depends critically on the exact position occupied by the aluminum atoms in the random network. As a consequence, it is argued that the exact mechanism of the observed metal-insulator transition cannot be studied if the atomic structure of the alloy is not already well understood.