Direct observation of a systematic spatial distribution pattern of structural vacancies in an In2Te3 crystal

Identifying the nature of domain structures within crystals is crucial for researching A₂IIIB₃VI compounds aimed at microelectronics applications. This paper provides a credible and convincing set of microscopic data on the domain structure formed in the high-temperature phase of an In₂Te₃ crystal (zinc-blende type structure), resolving a long-standing debate regarding the domain boundaries and structural vacancies in this crystal family. The crystal exhibited a finely subdivided matrix comprising parallelogram-shaped domains, each bounded by {111} planes. The domain boundaries were identified as a type of 180^∘{} domain wall, across which the crystal structure underwent a unit-cell inversion between parallel and antiparallel states. The domain interiors comprised a series of regionally varied structural units according to a statistically random, but a systematic spatial distribution pattern of structural vacancies induced along the [001] type direction. Consequently, the local structure gradually reversed between the two opposite corners defined along the longitudinal axis of each domain.