Generation and performance of special quasirandom structures for studying the elastic properties of random alloys: Application to Al-Ti

The performance of special-quasirandom structures (SQSs) for the description of elastic properties of random alloys was evaluated. A set of system-independent 32-atom-fcc SQS spanning the entire concentration range was generated and used to determine C(11), C(12), and C(44) of binary random substitutional AlTi alloys. The elastic properties of these alloys could be described using the set of SQS with an accuracy comparable to the accuracy achievable by statistical sampling of the configurational space of 3 x 3 x 3 (108 atom, C(44)) and 4 x 4 x 4 (256 atom, C(11) and C(12)) fcc supercells, irrespective of the impurity concentration. The smaller system size makes the proposed SQS ideal candidates for the ab initio determination of the elastic constants of random substitutional alloys. The set of optimized SQS is provided.