There has been considerable interest in chalcogenide alloys with high concentrations of native vacancies that lead to properties desirable for thermoelectric and phase-change materials. Recently, vacancy ordering has been identified as the mechanism for metal-insulator transitions observed in GeSb2Te4 and an unexpectedly low thermal conductivity in Ga2Te3. Here, we report the direct observation of vacancy ordering in Ga2SeTe2 utilizing aberration-corrected electron microscopy. Images reveal a cation-anion dumbbell inversion associated with the accommodation of vacancy ordering across the entire crystal. The result is a striking example of the interplay between native defects and local structure.
@article{arxiv.1312.5387,
title = {Probing the local environment of two-dimensional ordered vacancy structures in Ga2SeTe2 via aberration-corrected electron microscopy},
author = {Najeb Abdul-Jabbar and Peter Ercius and Ronald Gronsky and Edith Bourret-Courchesne and Brian Wirth},
journal= {arXiv preprint arXiv:1312.5387},
year = {2015}
}