Ab initio and shell model studies of structural, thermoelastic and vibrational properties of SnO2 under pressure

The pressure dependences of the structural, thermoelastic and vibrational properties of SnO2 in its rutile phase are studied, as well as the pressure-induced transition to a CaCl2-type phase. These studies have been performed by means of ab initio (AI) density functional theory calculations using th...

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Autores principales: Casali, Ricardo Antonio, Lasave, Jorge Augusto, Caravaca, María de los Ángeles, Koval, Sergio Fabián, Ponce Altamirano, Claudio Ariel, Migoni, Ricardo Luis
Formato: Artículo
Lenguaje:Inglés
Publicado: IOP Publishing 2026
Materias:
Phonos
Elasticity
Ab Initio
Shell Model
Sno2
Acceso en línea:http://repositorio.unne.edu.ar/handle/123456789/59996
Aporte de:
RIUNNE - Repositorio Institucional de la Universidad Nacional del Nordeste (UNNE) de Universidad Nacional del Nordeste
id I48-R184-123456789-59996
record_format dspace
spelling I48-R184-123456789-599962026-02-05T14:49:53Z Ab initio and shell model studies of structural, thermoelastic and vibrational properties of SnO2 under pressure Casali, Ricardo Antonio Lasave, Jorge Augusto Caravaca, María de los Ángeles Koval, Sergio Fabián Ponce Altamirano, Claudio Ariel Migoni, Ricardo Luis Phonos Elasticity Ab Initio Shell Model Sno2 The pressure dependences of the structural, thermoelastic and vibrational properties of SnO2 in its rutile phase are studied, as well as the pressure-induced transition to a CaCl2-type phase. These studies have been performed by means of ab initio (AI) density functional theory calculations using the localized basis code SIESTA. The results are employed to develop a shell model (SM) for application in future studies of nanostructured SnO2. A good agreement of the SM results for the pressure dependences of the above properties with the ones obtained from present and previous AI calculations as well as from experiments is achieved. The transition is characterized by a rotation of the Sn-centered oxygen octahedra around the tetragonal axis through the Sn. This rotation breaks the tetragonal symmetry of the lattice and an orthorhombic distortion appears above the critical pressure Pc. A zone-center phonon of B1g symmetry in the rutile phase involves such rotation and softens on approaching Pc. It becomes an Ag mode which stabilizes with increasing pressure in the CaCl2 phase. This behavior, together with the softening of the shear modulus .C11 C12/ 2 related to the orthorhombic distortion, allows a precise determination of a value for Pc. An additional determination is provided by the splitting of the basal plane lattice parameters. Both the AI and the experimentally observed softening of the B1g mode are incomplete, indicating a small discontinuity at the transition. However, all results show continuous changes in volume and lattice parameters, indicating a second-order transition. All these results indicate that there should be sufficient confidence for the future employment of the shell model. 2026-02-05T13:22:28Z 2026-02-05T13:22:28Z 2013 Artículo Casali, Ricardo Antonio, et al., 2013. Ab initio and shell model studies of structural, thermoelastic and vibrational properties of SnO2 under pressure. Journal of Physics: Condensed Matter. Londres: IOP Publishing, vol. 25, no. 13, p. 1-11. E-ISSN 0953-8984. http://repositorio.unne.edu.ar/handle/123456789/59996 eng http://dx.doi.org/10.1088/0953-8984/25/13/135404 openAccess http://creativecommons.org/licenses/by-nc-nd/2.5/ar/ application/pdf p. 1-11 application/pdf IOP Publishing Journal of Physics: Condensed Matter, 2013, vol. 25, no. 13, p. 1-11.
institution Universidad Nacional del Nordeste
institution_str I-48
repository_str R-184
collection RIUNNE - Repositorio Institucional de la Universidad Nacional del Nordeste (UNNE)
language Inglés
topic Phonos
Elasticity
Ab Initio
Shell Model
Sno2
spellingShingle Phonos
Elasticity
Ab Initio
Shell Model
Sno2
Casali, Ricardo Antonio
Lasave, Jorge Augusto
Caravaca, María de los Ángeles
Koval, Sergio Fabián
Ponce Altamirano, Claudio Ariel
Migoni, Ricardo Luis
Ab initio and shell model studies of structural, thermoelastic and vibrational properties of SnO2 under pressure
topic_facet Phonos
Elasticity
Ab Initio
Shell Model
Sno2
description The pressure dependences of the structural, thermoelastic and vibrational properties of SnO2 in its rutile phase are studied, as well as the pressure-induced transition to a CaCl2-type phase. These studies have been performed by means of ab initio (AI) density functional theory calculations using the localized basis code SIESTA. The results are employed to develop a shell model (SM) for application in future studies of nanostructured SnO2. A good agreement of the SM results for the pressure dependences of the above properties with the ones obtained from present and previous AI calculations as well as from experiments is achieved. The transition is characterized by a rotation of the Sn-centered oxygen octahedra around the tetragonal axis through the Sn. This rotation breaks the tetragonal symmetry of the lattice and an orthorhombic distortion appears above the critical pressure Pc. A zone-center phonon of B1g symmetry in the rutile phase involves such rotation and softens on approaching Pc. It becomes an Ag mode which stabilizes with increasing pressure in the CaCl2 phase. This behavior, together with the softening of the shear modulus .C11 C12/ 2 related to the orthorhombic distortion, allows a precise determination of a value for Pc. An additional determination is provided by the splitting of the basal plane lattice parameters. Both the AI and the experimentally observed softening of the B1g mode are incomplete, indicating a small discontinuity at the transition. However, all results show continuous changes in volume and lattice parameters, indicating a second-order transition. All these results indicate that there should be sufficient confidence for the future employment of the shell model.
format Artículo
author Casali, Ricardo Antonio
Lasave, Jorge Augusto
Caravaca, María de los Ángeles
Koval, Sergio Fabián
Ponce Altamirano, Claudio Ariel
Migoni, Ricardo Luis
author_facet Casali, Ricardo Antonio
Lasave, Jorge Augusto
Caravaca, María de los Ángeles
Koval, Sergio Fabián
Ponce Altamirano, Claudio Ariel
Migoni, Ricardo Luis
author_sort Casali, Ricardo Antonio
title Ab initio and shell model studies of structural, thermoelastic and vibrational properties of SnO2 under pressure
title_short Ab initio and shell model studies of structural, thermoelastic and vibrational properties of SnO2 under pressure
title_full Ab initio and shell model studies of structural, thermoelastic and vibrational properties of SnO2 under pressure
title_fullStr Ab initio and shell model studies of structural, thermoelastic and vibrational properties of SnO2 under pressure
title_full_unstemmed Ab initio and shell model studies of structural, thermoelastic and vibrational properties of SnO2 under pressure
title_sort ab initio and shell model studies of structural, thermoelastic and vibrational properties of sno2 under pressure
publisher IOP Publishing
publishDate 2026
url http://repositorio.unne.edu.ar/handle/123456789/59996
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