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dc.contributor.authorSmith, Den
dc.contributor.authorLawler, KVen
dc.contributor.authorMartinez-Canales, Men
dc.contributor.authorDaykin, AWen
dc.contributor.authorFussell, Zen
dc.contributor.authorSmith, GAen
dc.contributor.authorChilds, Cen
dc.contributor.authorSmith, JSen
dc.contributor.authorPickard, Christopheren
dc.contributor.authorSalamat, Aen
dc.date.accessioned2018-03-20T10:35:11Z
dc.date.available2018-03-20T10:35:11Z
dc.date.issued2018-01-31en
dc.identifier.issn2475-9953
dc.identifier.urihttps://www.repository.cam.ac.uk/handle/1810/274102
dc.description.abstractThe stability, structure and properties of carbonate minerals at lower mantle conditions has significant impact on our understanding of the global carbon cycle and the composition of the interior of the Earth. In recent years, there has been significant interest in the behavior of carbonates at lower mantle conditions, specifically in their carbon hybridization, which has relevance for the storage of carbon within the deep mantle. Using high-pressure synchrotron X-ray diffraction in a diamond anvil cell coupled with direct laser heating of CaCO3 using a CO2 laser, we identify a crystalline phase of the material above 40 GPa − corresponding to a lower mantle depth of around 1,000 km − which has first been predicted by ab initio structure predictions. The observed sp2 carbon hybridized species at 40 GPa is monoclinic with P21/c symmetry and is stable up to 50 GPa, above which it transforms into a structure which cannot be indexed by existing known phases. A combination of ab initio random structure search (AIRSS) and quasi-harmonic approximation (QHA) calculations are used to re-explore the relative phase stabilities of the rich phase diagram of CaCO3. Nudged elastic band (NEB) calculations are used to investigate the reaction mechanisms between relevant crystal phases of CaCO3 and we postulate that the mineral is capable of undergoing sp2-sp3 hybridization change purely in the P21/c structure − forgoing the accepted post-aragonite Pmmn structure.
dc.publisherAPS
dc.titlePostaragonite phases of CaCO3 at lower mantle pressuresen
dc.typeArticle
prism.issueIdentifier1en
prism.publicationDate2018en
prism.publicationNamePhysical Review Materialsen
prism.volume2en
dc.identifier.doi10.17863/CAM.21190
dcterms.dateAccepted2017-12-19en
rioxxterms.versionofrecord10.1103/PhysRevMaterials.2.013605en
rioxxterms.versionAM*
rioxxterms.licenseref.urihttp://www.rioxx.net/licenses/all-rights-reserveden
rioxxterms.licenseref.startdate2018-01-31en
dc.contributor.orcidPickard, Christopher [0000-0002-9684-5432]
dc.identifier.eissn2475-9953
rioxxterms.typeJournal Article/Reviewen
pubs.funder-project-idRoyal Society (WM150023)
pubs.funder-project-idEPSRC (EP/P022596/1)
rioxxterms.freetoread.startdate2019-01-31


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