Pressure-induced Jahn-Teller suppression in Rb{sub 2}CuCl{sub 4}(H{sub 2}O){sub 2}: Pseudo-Jahn-Teller effect
- DCITIMAC, Facultad de Ciencias, Universidad de Cantabria, Santander 39005 (Spain)
- Departmento de Fisica Aplicada, Universidad de Cantabria, Santander 39005 (Spain)
- Universite Pierre et Marie Curie, B77 4 Place Jussieu 75252 Paris Cedex 05 (France)
- LURE, Universite Paris-Sud, BP34, 91898 Orsay Cedex (France)
In this work we investigate the variation of the local structure around Cu{sup 2+} as well as the crystal structure in Rb{sub 2}CuCl{sub 4}(H{sub 2}O){sub 2} through x-ray absorption spectroscopy (XAS) and x-ray diffraction (XRD) as a function of pressure. We show that the application of pressure induces a local structural change in the Jahn-Teller (JT) CuCl{sub 4}(H{sub 2}O){sub 2}{sup 2-} complex from an axially elongated complex to a compressed one, yielding disappearance of the JT distortion related to the four in-plane Cl{sup -} ligands, which are responsible for the antiferrodistortive structure displayed by the crystal at ambient pressure. According to the Pseudo-Jahn-Teller (PJT) theory (electron-phonon coupling Exe), the presence of water ligands enhances the JT release at pressures well below the metallization pressure. The results are compared with recent pressure experiments on A{sub 2}CuCl{sub 4} layered perovskites and heteronuclear CuCl{sub 4}L{sub 2} complex series, L :Cl{yields}H{sub 2}O{yields}NH{sub 3}, and explained on the basis of the PJT model.
- OSTI ID:
- 20662255
- Journal Information:
- Physical Review. B, Condensed Matter and Materials Physics, Vol. 70, Issue 21; Other Information: DOI: 10.1103/PhysRevB.70.214104; (c) 2004 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA); ISSN 1098-0121
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ABSORPTION SPECTROSCOPY
CHLORIDES
CHLORINE IONS
COPPER COMPOUNDS
COPPER IONS
CRYSTAL STRUCTURE
CRYSTALS
ELECTRON-PHONON COUPLING
JAHN-TELLER EFFECT
LIGANDS
PEROVSKITES
PHASE TRANSFORMATIONS
PRESSURE DEPENDENCE
RUBIDIUM COMPOUNDS
X-RAY DIFFRACTION
X-RAY SPECTRA
X-RAY SPECTROSCOPY