Alloy broadening of impurity electronic spectra: One-dimensional tight-binding theory for a binary alloy

Abstract

A quantitative theory of inhomogeneous alloy broadening of impurity spectral lines is developed for substitutional crystalline alloys, with the use of the embedded-cluster method. Model calculations are presented for a defect in a tight-binding, one-state-per-atom, one-dimensional binary-alloy crystal $A_x{B}_{1-x}$ with nearest-neighbor interactions. Among the interesting effects discussed are the splitting of the impurity spectral lines into components which can be identified with the near-neighbor environment of the impurity and the dependence of these lines on both the alloy composition $x$ and the $A-B$ atomic-energy difference.