Spectral densities and complex band structures of random alloys - Augmented space recursion in reciprocal space

We present a formalism of calculating configuration averaged physical quantities of random alloys in reciprocal space going beyond single-site coherent potential approximation (CPA). The formalism constitutes augmented space recursive technique combined with first-principles tight-binding linearized muffin tin orbital (TBLMTO) method. Spectral densities and complex band structures of disordered f.c.c. AgPd and b.c.c. TiFe alloys have been calculated. The results are in excellent agreement with previous calculations.