Ab initio augmented space recursion to study complex multicomponent materials: application to the pseudobinary alloy Ni_1-xPt_xAl

Abstract

Using first-principles density-functional calculations, we studied the electronic structure and phase stability of the pseudobinary alloys. The calculations have been carried out using the augmented space recursion based on the all electron, tight-binding linear muffin-tin orbital basis. This work, in particular, provides a further generalization of our earlier developed technique to the case of systems of multiple sublattices with varying degree of disorder on them. We showcase the feasibility of our formalism by applying to a face-centered tetragonal-based pseudobinary (Ni_1-xPt_x)₃Al alloy system. Based on the calculation of effective pair interactions and their lattice Fourier transform, our phase stability search yields two stable superordered structures, namely, L1₀-type Ni₂PtAl and L1₀-type NiPt₂Al of which the latter has been observed experimentally. An estimate of the minima in the effective pair potential surface V(k) predicted the order-disorder transition temperatures of the two stable structures to be ∼1027 and ∼1379 K, respectively. The results are in agreement with the previous findings, proving the effectiveness of augmented space recursive technique in dealing with systems of multiple sublattices with varying degree of disorder on them. Our calculated additional physical quantities such as short-range order maps can be compared with future experimental studies.