Topics in the Electronic Theory of Solids.
Abstract
A tightbinding model Hamiltonian, used to study the electronic properties of a disordered alloy, is presented. Both the local energy levels and the interatomic transfer integrals were allowed to vary randomly. The problem is simplified considerably if it is assumed that the values of the transfer integrals are additive. The conventional methods of perturbation theory were applicable, and a meanfield approach, analogous to the coherentpotential approximation (CPA), was formulated. The resulting equations were compared to exact results concerning the dilute and splitband limits. It was concluded that, regarding the problem of additive offdiagonal disorder, an unambiguous generalization of the CPA was properly formulated. Also studied was positron annihilation anqular distributions in aluminum. Within the context of an independent particle model for positron annihilation, two photon angular correlation distributions were calculated in aluminum. Good agreement between theory and experiment was obtained with respect to many of the features in the angular distributions.
 Publication:

Ph.D. Thesis
 Pub Date:
 1975
 Bibcode:
 1975PhDT........21K
 Keywords:

 Physics: Condensed Matter;
 Angular Distribution;
 Atomic Structure;
 Metals;
 Positron Annihilation;
 Approximation;
 Energy Levels;
 Hamiltonian Functions;
 Mathematical Models;
 Perturbation Theory;
 Photons;
 SolidState Physics