We investigated L11-type ordering due to surface step migration in III-V semiconductor alloys of (A0.5B0.5)IIICV, using an Ising-like crystal growth model. A surface step along the  direction (the  step), which has a preference for unlike-atom pairs along the step, bears (111) and (111) variants (CuPtB-type) of the four possible L11 variants. On the other hand, a surface step along the  direction (the  step), which has a preference for like-atom pairs, produces either of the two CuPtB-type variants depending on the direction of the step motion. Antiphase boundaries are inserted parallel to (001) planes in the former case, and (111) or (111) in the latter case. The ordering rate in the case of the  step is larger than that for  step migration. These results explain well the previous experimental results obtained by transmission electron microscopy.
All Science Journal Classification (ASJC) codes
- Condensed Matter Physics
- Inorganic Chemistry
- Materials Chemistry