Relaxation and tunnelling of structural units within the LTO phase of La2CuO4
- 1. Arcavacata di Rende, Cosenza, Univ. della Calabria (Italy). Dip. di Fisica
- 2. Istituto Nazionale di Fisica della Materia, Rome (Italy)
- 3. Rome, Univ. 'La Sapienza' (Italy). Dip. di Fisica
- 4. Centro Nazionale delle Ricerche, Rome (Italy). Area di Ricerca di Roma-Tor Vergata. Ist. di Acustica 'O.M. Corbino'
- 5. Bauru, SP, Univeridade Estadual Paulista (Brazil). Dep. de Fisica
Description
The anelastic relaxation (elastic energy loss and Young modulus) of nearly stoichiometric La2CuO structure was measured. Extraordinarily intense effects are present below room temperature in the elastic dynamic susceptibility, indicating relaxational dynamics of a relevant fraction of the lattice. The involved degrees of freedom are identified as rotations of the CuO6 octahedra. Two distinct processes are found a frequencies around 1kHz: one is observed around 150 K and is characterized by a mean activation energy of 2800 K; the second one occurs below 30 K and is governed by atomic tunnelling. Two explanations are proposed for the faster process: 1)formation of fluctuating LTT domains on a scale of few atomic cells; 2) the LTO phase is a dynamical Jahn-Teller phase with all the octahedra tunnelling between two LTT-like tilts. In both cases there would be important implications regarding the mechanisms giving rise to charge nanophase separation and strong electron-phonon coupling
Additional details
Publishing Information
- Journal Title
- Nuovo Cimento. D
- Journal Volume
- 20D
- Journal Issue
- 7-8
- Journal Page Range
- p. 1127-1134
- ISSN
- 0392-6737
- CODEN
- NCSDDN
INIS
- Country of Publication
- Italy
- Country of Input or Organization
- Italy
- INIS RN
- 30016185
- Subject category
- S36: MATERIALS SCIENCE;
- Descriptors DEI
- CUPRATES; MECHANICAL PROPERTIES; STRESS RELAXATION; TUNNEL EFFECT; YOUNG MODULUS
- Descriptors DEC
- COPPER COMPOUNDS; MECHANICAL PROPERTIES; OXYGEN COMPOUNDS; TRANSITION ELEMENT COMPOUNDS