eprintid: 99227 rev_number: 60 eprint_status: archive userid: 608 dir: disk0/00/09/92/27 datestamp: 2010-10-19 17:20:40 lastmod: 2021-11-07 00:43:51 status_changed: 2012-08-22 16:10:41 type: article metadata_visibility: show item_issues_count: 0 creators_name: Caracas, R creators_name: Wentzcovitch, R creators_name: Price, GD creators_name: Brodholt, J title: CaSiO3 perovskite at lower mantle pressures ispublished: pub divisions: UCL divisions: B04 divisions: C06 divisions: F57 keywords: Earths lower mantle, Equation-of-state, Phase-transition, Tilted octahedra, Normal-mode, Stability, GPa, Elasticity, Constraints, Petrology note: Copyright 2005 by the American Geophysical Union abstract: We investigate by first-principles the structural behavior of CaSiO3 perovskite up to lower mantle pressures. We confirm that the cubic perovskite modification is unstable at all pressures. The zero Kelvin structure is stabilized by SiO6 octahedral rotations that lower the symmetry to tetragonal, orthorhombic, rhombohedral, or to a cubic supercell. The resulting structures have comparable energies and equation of state parameters. This suggests that relatively small deviatoric/ shear stresses might induce phase transformations between these various structures softening some elastic moduli, primarily the shear modulus. The seismic signature accompanying a local increase in CaSiO3 content should be a positive density anomaly and a negative V-S anomaly. date: 2005-03-23 publisher: AMER GEOPHYSICAL UNION official_url: http://dx.doi.org/10.1029/2004GL022144 vfaculties: VMPS oa_status: green language: eng primo: open primo_central: open_green article_type_text: Article verified: verified_batch elements_source: Web of Science elements_id: 71728 doi: 10.1029/2004GL022144 language_elements: EN lyricists_name: Brodholt, John lyricists_name: Price, Geoffrey lyricists_id: JPBRO15 lyricists_id: GDPRI11 full_text_status: public publication: Geophysical Research Letters volume: 32 number: 6 article_number: L06306 issn: 0094-8276 citation: Caracas, R; Wentzcovitch, R; Price, GD; Brodholt, J; (2005) CaSiO3 perovskite at lower mantle pressures. Geophysical Research Letters , 32 (6) , Article L06306. 10.1029/2004GL022144 <https://doi.org/10.1029/2004GL022144>. Green open access document_url: https://discovery.ucl.ac.uk/id/eprint/99227/1/2004GL022144.pdf