Effect of Local Order on Energy Bands in Binary Alloys
Abstract
Equations are developed giving the dependence of the energy band shape on the state of local and longrange order in an alloy. The approximation used is the "emptylattice virtual crystal" model, in which a free electron gas is perturbed by a fluctuating potential of zero average value. The energy correction is expressed in terms of the nearestneighbor order parameter α and longrange parameter λ this is done with the aid of a qualitative formula giving nonnearestneighbor parameters as functions of α. The result is evaluated numerically, and it is shown how the band bottom gets squeezed out into a long tail as α proceeds from the perfect shortrange order > random > clustered cases. The effect of longrange order is discussed and the conclusions are compared with those of a previous tightbinding calculation.
 Publication:

Physical Review
 Pub Date:
 August 1962
 DOI:
 10.1103/PhysRev.127.738
 Bibcode:
 1962PhRv..127..738M