High-pressure Raman investigation of high index facets bounded α-Fe2O3 pseudocubic crystals

J Phys Condens Matter. 2020 Dec 8;33(8):085701. doi: 10.1088/1361-648X/abcb11. Online ahead of print.

Abstract

High index facet bounded α-Fe2O3 pseudocubic crystals has gained the attention of the scientific community due to its promising electrochemical sensing response towards aqueous ammonia. The structural stability of α-Fe2O3 pseudocubic crystals is investigated through high-pressure Raman spectroscopy up to 22.2 GPa, and those results are compared with our ab initio theoretical calculations. The symmetry of the experimental Raman-active modes has been assigned by comparison with theoretical data. In addition to the Raman-active modes, two additional Raman features are also detected, whose intensity increases with compression. The origin of these two additional peaks addressed in this study, reveals a strong dependence on the geometry and the low dimensionality as the most plausible explanation.