LOW-TEMPERATURE AMORPHIZATION AT INTERFACES IN LAYERED STRUCTURES - EVIDENCE FOR A LOW-DIMENSIONAL PEIERLS SYSTEM

Interface reactions were observed by means of photoelectron spectrosco py during the preparation of Au/Sn bilayers at 77 K. These reactions l ead to ultra-thin (0.5-2 nm) amorphous layers with tunable stoichiomet ry, spanning the same range of compositions as found for the correspon ding vapor-quenched amorphous Hume-Rothery alloys. in all cases, struc ture-induced minima in the electronic density of states at the Fermi l evel are observed for the intermixed amorphous phases. Since structure -induced minima are a characteristic feature of a Peierls system, the ultra-thin amorphous layers may be discussed as reflecting the transit ion from a nearly two-dimensional to an isotropic three-dimensional Pe ierls-distorted system.