Direct observation of Jahn-Teller critical dynamics at a charge-order Verwey transition

By means of diffuse x-ray scattering (DS) and inelastic x-ray scattering (IXS), we probe directly the charge-ordering (CO) dynamics in the Verwey system (NaMn3)Mn4O12, where a peculiar quadruple perovskite structure with no oxygen disorder stabilizes a nearly full Mn3+/Mn4+ static charge order at TC...

Full description

Saved in:
Bibliographic Details
Published in:Physical review. B 2021-12, Vol.104 (23), Article 235114
Main Authors: Pascotto Gastaldo, Vinícius, Rao, Mala N., Bosak, Alexey, d'Astuto, Matteo, Prodi, Andrea, Verseils, Marine, Klein, Yannick, Bellin, Christophe, Paolasini, Luigi, de Oliveira, Adilson J. A., Gilioli, Edmondo, Chaplot, Samrath Lal, Gauzzi, Andrea
Format: Article
Language:English
Subjects:
Condensed Matter
Physics
Strongly Correlated Electrons
Citations: Items that this one cites
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:By means of diffuse x-ray scattering (DS) and inelastic x-ray scattering (IXS), we probe directly the charge-ordering (CO) dynamics in the Verwey system (NaMn3)Mn4O12, where a peculiar quadruple perovskite structure with no oxygen disorder stabilizes a nearly full Mn3+/Mn4+ static charge order at TCO=175 K concomitant to a commensurate structural modulation with propagation vector qCO=(1/2,1/2,0). At TCO, the IXS spectra unveil a softening of a 35.3-meV phonon at qCO. Lattice dynamical calculations enable us to attribute this soft phonon to an Ag mode whose polarization matches the Jahn-Teller-like distortion pattern of the structural modulation. This result demonstrates that the Jahn-Teller instability is the driving force of the CO Verwey transition in (NaMn3)Mn4O12, thus elucidating a long-standing controversy regarding the mechanism of this transition observed in other mixed-valence systems like magnetite.
ISSN:2469-9950
2469-9969
DOI:10.1103/PhysRevB.104.235114