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SLAC Publication: SLAC-PUB-14289
SLAC Release Date: August 12, 2011
High-Pressure Evolution of Fe2O3 Electronic Structure Revealed by X-ray Absorption
Kao, Chi-Chang.
We report the high-pressure measurement of the Fe?K edge in hematite (Fe2O3) by x-ray absorption spectroscopy in partial fluorescence yield geometry. The pressure-induced evolution of the electronic structure as Fe2O3 transforms from a high-spin insulator to a low-spin metal is reflected in the x-ray absorption pre-edge. The crystal-field splitting energy was found to increase monotonically with pressure up to 48 GPa, above which a series of phase transitions occur. Atomic multiplet, cluster dia... Show Full Abstract
We report the high-pressure measurement of the Fe?K edge in hematite (Fe2O3) by x-ray absorption spectroscopy in partial fluorescence yield geometry. The pressure-induced evolution of the electronic structure as Fe2O3 transforms from a high-spin insulator to a low-spin metal is reflected in the x-ray absorption pre-edge. The crystal-field splitting energy was found to increase monotonically with pressure up to 48 GPa, above which a series of phase transitions occur. Atomic multiplet, cluster diagonalization, and density-functional calculations were performed to simulate the pre-edge absorption spectra, showing good qualitative agreement with the measurements. The mechanism for the pressure-induced electronic phase transitions of Fe2O3 is discussed and it is shown that ligand hybridization significantly reduces the critical high-spin/low-spin transition pressure. Show Partial Abstract
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  • Interest Categories: Material Sciences