Keywords

nonstoichiometry, vacancy ordering, alloys, first-principle calculations, ground states

Abstract

Whereas nearly all compounds AnBm obey Dalton's rule of integer stoichiometry (n:m, both integer), there is a class of systems, exemplified by the rocksalt structure Sc1-x□xS, that exhibits large deviations from stoichiometry via vacancies, even at low temperatures. By combining first-principles total energy calculations with lattice statistical mechanics, we scan an astronomical number of possible structures, identifying the stable ground states. Surprisingly, all have the same motifs: (111) planes with (112) vacancy rows arranged in (110) columns. Electronic structure calculations of the ground states (identified out of ~3 × 10^6 structures) reveal the remarkable origins of nonstoichiometry.

Original Publication Citation

G. L. W. Hart and A. Zunger, "Origins of Non-stoichiometry and Vacancy Ordering in Sc1-xVacxS," Phys. Rev. Lett. 87 27558 (21). The original article may be found here: http://prl.aps.org/abstract/PRL/v87/i27/e27558