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Leroux, M., Le Tacon, M., Calandra, M., Cario, L., Measson, M. .-A., Diener, P., Borrissenko, E., Bosak, A. & Rodiere, P. (2012) Anharmonic suppression of charge density waves in 2H-NbS2. Phys. Rev. B, 86 155125.
Added by: Laurent Cournède (2016-03-10 21:28:38) |
| Type de référence: Article DOI: 10.1103/PhysRevB.86.155125 Numéro d'identification (ISBN etc.): 1098-0121 Clé BibTeX: Leroux2012 Voir tous les détails bibliographiques  |
Catégories: PMN Mots-clés: lattice, model, spectroscopy, state, superconductivity, transitions Créateurs: Borrissenko, Bosak, Calandra, Cario, Diener, Le Tacon, Leroux, Measson, Rodiere Collection: Phys. Rev. B |
Consultations : 1/628
Indice de consultation : 4% Indice de popularité : 1% |
| Résumé |
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The temperature dependence of the phonon spectrum in the superconducting transition-metal dichalcogenide 2H-NbS2 is measured by diffuse and inelastic x-ray scattering. A deep, wide, and strongly temperature-dependent softening of the two lowest-energy longitudinal phonon bands appears along the Gamma Msymmetry line in reciprocal space. In sharp contrast to the isoelectronic compound 2H-NbSe2, the soft phonons energies are finite, even at very low temperature, and no charge density wave instability occurs, in disagreement with harmonic ab initio calculations. We show that 2H-NbS2 is at the verge of the charge density wave transition and its occurrence is only suppressed by the large anharmonic effects. Moreover, the anharmonicity and the electron phonon coupling both show a strong in-plane anisotropy.
Added by: Laurent Cournède |