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Further Analysis Of Electronic States In The Muffin-Tin Model Of A Disordered Alloy, L. Schwartz, A. Bansil

Arun Bansil

Several new results on the evaluation of the spectral function A(k⃗,E) and average density of states ρ(E) in a realistic model of a substitutional binary alloy are presented. This work is primarily concerned with the conditions under which a given approach can be relied upon to yield a non-negative spectrum. In the average t matrix and coherent-potential approximations, a link is established between the sign of A(k⃗,E) and the Argand diagram for the energy-shell matrix elements τL of the effective atomic scattering operators: If τL lies within the unitarity circle, then A(k⃗,E)>0. The connection between this result and our …