%0 Journal Article
%T Stability and Lattice Dynamics of Ruddlesden–Popper Tetragonal Sr 2 TiO 4
%+ Institut Charles Gerhardt Montpellier - Institut de Chimie Moléculaire et des Matériaux de Montpellier (ICGM)
%+ (nano)Matériaux pour l'énergie (ENERGIE)
%+ Laboratoire Nanotechnologies et Nanosystèmes [Sherbrooke] (LN2)
%+ Institut Interdisciplinaire d'Innovation Technologique [Sherbrooke] (3IT)
%+ Institut Laue-Langevin (ILL)
%+ Department of Quantum Matter Physics [Geneva] (DQMP)
%+ Laboratoire Charles Coulomb (L2C)
%A Viennois, Romain
%A Hermet, P.
%A Machon, D.
%A Koza, M.
%A Bourgogne, D.
%A Fraisse, B.
%A Petrović, A.
%A Maurin, D.
%< avec comité de lecture
%@ 1932-7447
%J Journal of Physical Chemistry C
%I American Chemical Society
%V 124
%N 51
%P 27882-27893
%8 2020-12-24
%D 2020
%R 10.1021/acs.jpcc.0c08237
%Z Chemical Sciences/Material chemistryJournal articles
%X We report a combined experimental and theoretical lattice dynamics study of the Ruddlesden–Popper layered compound Sr<sub>2</sub>TiO<sub>4</sub>. From inelastic neutron scattering experiments, we derive the generalized phonon density of states of Sr<sub>2</sub>TiO<sub>4</sub>. We also report its heat capacity, thermal expansion, and thermodynamic Grüneisen parameters using the calculated bulk modulus and find a large value of about 2. Using Raman scattering experiments under pressure, we discuss a potential structural distortion of the tetragonal structure above 11 GPa, which could be due to nonhydrostatic compression. The mode Grüneisen parameters of the four Raman-active modes are determined and shown to be in reasonable agreement with those obtained by density functional perturbation theory (DFPT) calculations. The temperature behavior of the Raman-active modes was studied, allowing us to determine the implicit volume and explicit anharmonic contributions. Above 400 K, the implicit volume contribution dominates the temperature-induced variation of the four Raman-active modes, whereas, below this temperature, the explicit anharmonic contribution is the dominant contributor to the highest energy mode. Our results underline the importance of anharmonicity in vibration-related properties of Sr<sub>2</sub>TiO<sub>4</sub>.
%G English
%2 https://hal.science/hal-03087910/document
%2 https://hal.science/hal-03087910/file/Art-Sr2TiO4-rev.pdf
%L hal-03087910
%U https://hal.science/hal-03087910
%~ UGA
%~ CNRS
%~ UNIV-LYON1
%~ INSA-LYON
%~ EC-LYON
%~ ENSC-MONTPELLIER
%~ ICG
%~ L2C
%~ INC-CNRS
%~ MIPS
%~ CHIMIE
%~ UNIV-MONTPELLIER
%~ LN2
%~ INSA-GROUPE
%~ ILM
%~ UDL
%~ UNIV-LYON
%~ TEST-HALCNRS
%~ UGA-EPE
%~ LN2-NRJ
%~ UM-2015-2021
%~ TEST2-HALCNRS