Anomalously Suppressed Thermal Conduction by Electron-Phonon Coupling in Charge-Density-Wave Tantalum Disulfide.
Adv Sci (Weinh)
; 7(11): 1902071, 2020 Jun.
Article
em En
| MEDLINE
| ID: mdl-32537392
ABSTRACT
Charge and thermal transport in a crystal is carried by free electrons and phonons (quantized lattice vibration), the two most fundamental quasiparticles. Above the Debye temperature of the crystal, phonon-mediated thermal conductivity (κ L) is typically limited by mutual scattering of phonons, which results in κ L decreasing with inverse temperature, whereas free electrons play a negligible role in κ L. Here, an unusual case in charge-density-wave tantalum disulfide (1T-TaS2) is reported, in which κ L is limited instead by phonon scattering with free electrons, resulting in a temperature-independent κ L. In this system, the conventional phonon-phonon scattering is alleviated by its uniquely structured phonon dispersions, while unusually strong electron-phonon (e-ph) coupling arises from its Fermi surface strongly nested at wavevectors in which phonons exhibit Kohn anomalies. The unusual temperature dependence of thermal conduction is found as a consequence of these effects. The finding reveals new physics of thermal conduction, offers a unique platform to probe e-ph interactions, and provides potential ways to control heat flow in materials with free charge carriers. The temperature-independent thermal conductivity may also find thermal management application as a special thermal interface material between two systems when the heat conduction between them needs to be maintained at a constant level.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Idioma:
En
Revista:
Adv Sci (Weinh)
Ano de publicação:
2020
Tipo de documento:
Article