Electronic effects in the order-disorder transition in β brass

The authors present first-principles one-electron calculations of angle-resolved photoemission spectra and electron-positron momentum densities in equiatomic Cu-Zn alloys ( beta brass). Many-body and instrumental effects are included by realistic phenomenological procedures. They predict that the changes in electronic structure across the order-disorder transformation should be clearly reflected in photoemission, and somewhat less pronounced in positron annihilation. They demonstrate, however, that the two techniques are complementary, and that combined studies should be a powerful probe of ordering phenomena at the electronic level.