Studies on Quantum Percolation

Abstract

Studies on the localisation in binary alloys (commonly termed as ‘quantum percolation’ problem) are reviewed highlighting the special features that this simple model has and which are absent in other models — the most prominent among them being the existence of extended states at infinite disorder. Some new scaling arguments are also reported that enable to predict qualitatively the behaviour of the participation ratio as function of concentration of one of the constituents of the alloy. These are substantiated by numerical simulation results. After summarising all'important approaches and their results, one of the important conclusions drawn is that in two‐dimensional binary alloys not all states are localised at any disorder, contrary to a recent belief. Copyright © 1983 WILEY‐VCH Verlag GmbH & Co. KGaA