Self-consistent LCAO-CPA method for disordered alloys

We present a scheme for calculating the electronic structure of disordered alloys, self-consistent in the local-density-approximation sense. It is based on expanding the one-electron Green's function in the basis of modified atomic orbitals [H. Eschrig, Optimized LCAO Method and the Electronic Structure of Extended Systems (Springer, Berlin, 1989)]. The two-terminal approximation introduced for the Hamiltonian and the overlap matrix permits us to treat both the diagonal and off-diagonal disorder using an extension of the Blackman-Esterling-Berk form of the coherent-potential approximation (CPA) [Phys. Rev. B 4, 2412 (1971)] to a nonorthogonal basis set. Calculations using the scalar relativistic density functional for the magnetic binary transition-metal alloys Fe-Co, Fe-Pt, Co-Pt, and for the ternary alloy Al-Fe-Mn give results comparing well with experimental data and calculations based on the Korringa-Kohn-Rostoker (KKR)-CPA and linear muffin-tin orbital-CPA techniques.