First-principles investigation of ordered structures in zinc blende III–V ternary semiconductors

We systematically investigate the impact of ordered configurations of group III atoms on the formation enthalpy of zinc blende III–V alloys using first-principles calculations. The study focuses on 12 quasibinary systems: AlxGa1−xN, AlxIn1−xN, GaxIn1−xN, AlxGa1−xP, AlxIn1−xP, GaxIn1−xP, AlxGa1−xAs, AlxIn1−xAs, GaxIn1−xAs, AlxGa1−xSb, AlxIn1−xSb, and GaxIn1−xSb. Since the spatial distribution of group III cations in the zinc blende structure is equivalent to that in a face-centered cubic (FCC) lattice, FCC-based ordered phases are employed to compare formation enthalpies across different configurations. For compositions of x = 0.25 and 0.75, we compare the formation enthalpies of three ordered structures—L12, D023, and D022—with those of a random solid solution (RSS), in which group III elements are randomly distributed. At x = 0.5, four ordered structures—L10, L11, Y2, and chalcopyrite—are evaluated in comparison with the RSS structure. Our results reveal that for AlxGa1−xP, AlxGa1−xAs, and AlxGa1−xSb at x = 0.25 and 0.75, the RSS structure exhibits the lowest formation enthalpy, indicating a thermodynamic preference for disordered configurations. In contrast, at x = 0.5, the L11 structure is the most stable for these systems. For the remaining quasibinary systems, the D022 and chalcopyrite structures are energetically favored. However, all minimum formation enthalpies remain positive, suggesting that the ordered phases are thermodynamically metastable across the studied compositions. These findings offer fundamental insights into the relationship between atomistic ordering and formation enthalpy in III–V alloys, thereby providing a theoretical basis for predictive modeling and guiding future experimental efforts in materials design.