ELECTRON MOMENTUM DENSITY IN DISORDERED MUFFIN-TIN CU1-XNIX IN THE AVERAGE-T-MATRIX APPROXIMATION

In an earlier article we discussed the formalism for evaluating the average electron-momentum density in a random binary alloy by using the average-t-matrix approximation to treat the disorder and muffin-tin potentials to represent the constituent atoms. The present paper considers the application of this formalism to Cu1-xNix over a range of alloy compositions. The characteristic effects of disorder on the spectral momentum density ρ(p→,E) are delineated. In discussing the momentum density ρ(p→) we focus on how this quantity changes as x increases from 0 to 1 and the Ni d band develops from a virtual bound state below the Fermi energy into a transition-metal d band interacting the Fermi energy. Our detailed predictions in this regard should be amenable to experimental verification by two-dimensional positron-annihilation experiments. © 1979 The American Physical Society.