Contradictory results of high-pressure studies in cubic bixbyite-type indium oxide (c-In2O3) at room temperature (RT) have motivated us to perform high-pressure powder x-ray diffraction and Raman scattering measurements in this material. On increasing pressure c-In2O3 undergoes a transition to the Rh2O3-II structure. On decreasing pressure Rh2O3-II-type In2O3 undergoes a transition to a previously unknown phase which is isostructural to Rh2O3-III. On further decrease of pressure, another phase transition to corundum-type In2O3, which is metastable at room conditions, is observed. Recompression of metastable corundum-type In2O3 shows that the Rh2O3-III phase is the post-corundum phase. Our results are supported by theoretical ab initio calculations which show that the Rh2O3-III phase could be present in other sesquioxides, thus leading to a revision of the pressure-temperature phase diagrams of sesquioxides.
@article{arxiv.1311.6725,
title = {Pbca-type In2O3: the lost pressure-induced post-corundum phase},
author = {Braulio García-Domene and Juan A. Sans and Óscar Gomis and Francisco J. Manjón and Henry M. Ortiz and Daniel Errandonea and David Santamaría-Pérez and Domingo Martínez-García and Rosario Vilaplana and André L. J. Pereira and Ángel Morales-García and Plácida Rodríguez-Hernández and Alfonso Muñoz and Catalin Popescu and Alfredo Segura},
journal= {arXiv preprint arXiv:1311.6725},
year = {2013}
}