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Grasset, R., Cea, T., Gallais, Y., Cazayous, M., Sacuto, A., Cario, L., Benfatto, L. & Measson, M.-A. (2018) Higgs-mode radiance and charge-density-wave order in 2H-NbSe2. Physical Review B, 97 094502.
Added by: Richard Baschera (2018-04-03 08:23:05) Last edited by: Richard Baschera (2018-04-03 08:23:57) |
| Type de référence: Article DOI: 10.1103/PhysRevB.97.094502 Clé BibTeX: Grasset2018 Voir tous les détails bibliographiques  |
Catégories: INTERNATIONAL, PMN Créateurs: Benfatto, Cario, Cazayous, Cea, Gallais, Grasset, Measson, Sacuto Collection: Physical Review B |
Consultations : 1/580
Indice de consultation : 5% Indice de popularité : 1.25% |
| Résumé |
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Despite being usually considered two competing phenomena, charge-density wave and superconductivity coexist in few systems, the most emblematic one being the transition-metal dichalcogenide 2H-NbSe2. This unusual condition is responsible for specific Raman signatures across the two phase transitions in this compound. While the appearance of a soft phonon mode is a well-established fingerprint of the charge-density-wave order, the nature of the sharp subgap mode emerging below the superconducting temperature is still under debate. In this work we use external pressure as a knob to unveil the delicate interplay between the two orders, and consequently the nature of the superconducting mode. Thanks to an advanced extreme-conditions Raman technique, we are able to follow the pressure evolution and the simultaneous collapse of the two intertwined charge-density-wave and superconducting modes. The comparison with microscopic calculations in a model system supports the Higgs-type nature of the superconducting mode and suggests that charge-density wave and superconductivity in 2H-NbSe2 involve mutual electronic degrees of freedom. These findings fill the knowledge gap on the electronic mechanisms at play in transition-metal dichalcogenides, a crucial step to fully exploit their properties in few-layer systems optimized for device applications.
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