L-dependent pseudopotential in the theory of band structure of disordered solids-an application to binary substitutional alloys MgLi, MgCd and MgIn

Abstract

In this work the authors extend the KKRZ method of band structure calculation for crystalline solids to the disordered systems of substitutional alloys and amorphous solids. In the case of substitutional alloys the average T-matrix approximation was employed whereby the l-dependent pseudopotential became complex, making the secular determinant complex. For amorphous solids, a positional averaging was taken following Kramer (1970), whereby a complex function phi nalpha (k+Kn,E) of a disorder parameter alpha appeared in the diagonal term of the secular determinant, again making the secular determinant complex. In both cases the energy eigenvalues obtained are complex in nature, the imaginary part being interpreted by a lifetime broadening of the energy state. Finally, the authors have applied this method to three binary substitutional alloys MgLi, MgCd and MgIn to obtain the complex energy band of these alloys. From these band structure data, density of states and optical properties have also been calculated and compared with the pure case.