Poster
16:30 | Experimental and theoretical study of SbPO4 under compression
| Authors: André Pereira (UFGD - Universidade Federal da Grande Dourados, UPV - Instituto de Diseño para la Fabricación y Producción Automatizada, MALTA Consolider Team, Universitat Politècnica de València) ; Rosario Vilaplana (UPV - Centro de Tecnologías Físicas, MALTA-Consolider Team, Universitat Politècnica de València) ; David Santamaria (UV - Departament de Física Aplicada – ICMUV, MALTA Consolider Team, Universitat de València) ; Daniel Errandonea (UV - Departament de Física Aplicada – ICMUV, MALTA Consolider Team, Universitat de València) ; Catalin Popescu (CELLS-ALBA - CELLS-ALBA Synchrotron Light Facility) ; Estelina Lora da Silva (UPV - Instituto de Diseño para la Fabricación y Producción Automatizada, MALTA Consolider Team, Universitat Politècnica de València) ; Juan Angel Sans (UPV - Instituto de Diseño para la Fabricación y Producción Automatizada, MALTA Consolider Team, Universitat Politècnica de València) ; Juan Rodríguez-carvajal (ILL - Institut Laue-Langevin) ; Alfonso Muñoz (ULL - Departamento de Física, Instituto de Materiales y Nanotecnología, MALTA Consolider Team) ; Placida Rodríguez-hernández (ULL - Departamento de Física, Instituto de Materiales y Nanotecnología, MALTA Consolider Team) ; Andres Mujica (ULL - Departamento de Física, Instituto de Materiales y Nanotecnología, MALTA Consolider Team) ; Silvana Elena Radescu (ULL - Departamento de Física, Instituto de Materiales y Nanotecnología, MALTA Consolider Team) ; Armando Beltrán (UJI - Departament de Química Física i Analítica, Universitat Jaume I de Castelló) ; Miguel Mollar (UPV - Instituto de Diseño para la Fabricación y Producción Automatizada, MALTA Consolider Team, Universitat Politècnica de València) ; Francisco Javier Manjón (UPV - Instituto de Diseño para la Fabricación y Producción Automatizada, MALTA Consolider Team, Universitat Politècnica de València) |
Abstract: SbPO4 is a monoclinic layered material characterized by a strong activity of the non-bonding lone electron pairs (LEPs) of Sb that leads to the formation of layers piled up along the a axis and linked by weak Sb-O electrostatic interactions. Due to the strong structural effect of LEPs, Sb has a fourfold coordination just as P despite the large difference in ionic radii between both elements. Here we report a joint experimental and theoretical study of the structural and vibrational properties of SbPO4 at high pressure. From the structural point of view, SbPO4 is a highly compressible material with considerable anisotropic behavior. The a-axis is highly compressible due to the strong compression of the LEPs and the weak interlayer Sb-O bonds. This large compressibility of the a-axis leads to a considerable increase of the Sb coordination with pressure (from 4 at room pressure to 6 around 20 GPa) without changing the crystalline structure. A pressure-induced phase transition is observed, whose onset is around 9 GPa and it is completed above 20 GPa, as confirmed by Raman spectroscopy measurements. Raman-active modes have been measured at different pressures and properly discussed. The good agreement observed between the experimental and theoretical data for structural and vibrational properties allows us to better understand the microscopic mechanism of the compression of monoclinic SbPO4, which exhibits an isostructural phase transition above 4 GPa, and predict possible high-pressure phases.
Acknowledgments: Authors thank the financial support from Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq - 159754/2018-6, 201050/2012-9), Spanish Ministerio de Economia y Competitividad (MINECO) under projects MALTA Consolider Ingenio 2010 network (MAT2015-71070-REDC), MAT2016-75586-C4-1/2/3-P and FIS2017-83295-P, from Generalitat Valenciana under project PROMETEO/2018/123 and from European Comission under project COMEX. E. L. d.-S., A. M. and P. R-H. acknowledge computing time provided by Red Española de Supercomputación (RES) and MALTA-Cluster.
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