%0 Conference Paper
%F Oral 
%T Elastic softness of hybrid lead halide perovskites
%+ Institut des Fonctions Optiques pour les Technologies de l'informatiON (FOTON)
%+ Institut des Sciences Chimiques de Rennes (ISCR)
%+ King Abdullah University of Science and Technology [Saudi Arabia] (KAUST)
%+ Magnétisme et Diffusion Neutronique (MDN)
%+ Institut de Physique de Rennes (IPR)
%+ Laboratoire Charles Coulomb (L2C)
%+ Laboratoire Léon Brillouin (LLB - UMR 12)
%A da Cunha Ferreira, Afonso
%A Létoublon, Antoine
%A Paofai, Serge
%A Saidaminov, Makhsud
%A Raymond, Stephane
%A Ecolivet, Claude
%A Ruffle, Benoit
%A Cordier, Stéphane
%A Katan, Claudine
%A Bakr, Osman, M
%A Even, Jacky
%A Bourges, Philippe
%< avec comité de lecture
%B Journées de la Diffusion Neutronique (JDN 2018)
%C Roquebrune-sur-Argens, France
%8 2018-05-14
%D 2018
%Z Physics [physics]
%Z Chemical SciencesConference papers
%X Much recent attention has been devoted towards unraveling the microscopic optoelectronic properties of hybrid organic-inorganic perovskites. Here we investigate by coherent inelastic neutron scattering spectroscopy and Brillouin light scattering, low frequency acoustic phonons in four different hybrid perovskite single crystals: MAPbBr_{3}, FAPbBr_{3}, MAPbI_{3}, and α-FAPbI_{3} (MA: methylammonium, FA: formamidinium). We report a complete set of elastic constants characterized by a very soft shear modulus C_{44}. Further, a tendency towards an incipient ferroelastic transition is observed in FAPbBr_{3}. We observe a systematic lower sound group velocity in the technologically important iodide-based compounds compared to the bromide-based ones. The findings suggest that low thermal conductivity and hot phonon bottleneck phenomena are expected to be enhanced by low elastic stiffness, particularly in the case of the ultrasoft α-FAPbI_{3}.
%G English
%L hal-01933567
%U https://hal.science/hal-01933567
%~ CEA
%~ INSTITUT-TELECOM
%~ UNIV-RENNES1
%~ UGA
%~ CNRS
%~ INSA-RENNES
%~ ENSC-RENNES
%~ FOTON
%~ FOTON-INSA
%~ OSUR
%~ L2C
%~ ISCR
%~ IPR
%~ FOTON_OHM
%~ ISCR-CTI
%~ ISCR-CSM
%~ INAC-SPSMS
%~ DSM-INAC
%~ ZZ-IPR-MN
%~ UR1-SPM
%~ INC-CNRS
%~ IRAMIS-LLB
%~ CEA-UPSAY
%~ UR1-UFR-SPM
%~ UR1-HAL
%~ UR1-MATH-STIC
%~ UR1-SDLM
%~ UNIV-PARIS-SACLAY
%~ CEA-UPSAY-SACLAY
%~ IPR-ML
%~ MIPS
%~ UNIV-MONTPELLIER
%~ CEA-DRF
%~ TEST-UR-CSS
%~ UNIV-RENNES
%~ INSA-GROUPE
%~ IRIG
%~ CEA-GRE
%~ TEST-HALCNRS
%~ UGA-COMUE
%~ UR1-MATH-NUM
%~ UR1-MMS
%~ GS-ENGINEERING
%~ IRAMIS
%~ GS-CHIMIE
%~ GS-PHYSIQUE
%~ UM-2015-2021
%~ TEST2-HALCNRS