Effect of the Emphasis Type="Italic"d/Emphasis

Authors: Koichiro Umemoto Renata M Wentzcovitch

Publish Date: 2010/12/14

Volume: 38, Issue: 5, Pages: 387-395

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Abstract

We present a systematic densityfunctional study of phase relations in three 4dtransitionmetal sesquioxides Y2O3 Rh2O3 and In2O3 Y2O3 and In2O3 undergo pressureinduced transitions to phases with larger cation coordination number from 6 to 7 at low pressures However this does not occur in Rh2O3 at least up to ~300 GPa This cannot be explained by usual arguments based on ionicradii ratios often used successfully to explain phase relations in simplemetal and rareearth sesquioxides and sesquisulfides Inspection of their electronic structures shows that in Rh2O3 the electronic occupancy of 4d orbitals 4d 6 plays a fundamental role in the extraordinary stability of the Rh2O3IItype phase with respect to coordination increase We point out that dorbital occupancy is a fundamental factor in explaining phase relations in transitionmetal sesquioxides and sesquisulfidesAll calculations have been performed using the QuantumESPRESSO distribution Giannozzi et al 2009 Charge densities were visualized using XCrySDen software Kokalj 2003 Research was supported by NSF grants NSF/EAR 0635990 and NSF/ATM 0428774 VLab Computations were performed at the Minnesota Supercomputing Institute

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