Localised Ag+ vibrations at the origin of ultralow thermal conductivity in layered thermoelectric AgCrSe2 - Normandie Université Access content directly
Journal Articles Scientific Reports Year : 2016

Localised Ag+ vibrations at the origin of ultralow thermal conductivity in layered thermoelectric AgCrSe2

Abstract

In materials science, the substructure approach consists in imagining complex materials in which a particular property is associated with a distinct structural feature, so as to combine different chosen physical characteristics, which otherwise have little chance to coexist. Applied to thermoelectric materials, it has been used to achieve simultaneously phonon-glass and electron-crystal properties. Mostly studied for its superionic conductivity, AgCrSe2 is a naturally layered compound, which achieves very low thermal conductivity, ∼0.4 W.K-1.m-1 at RT (room temperature), and is considered a promising thermoelectric. The Cr atoms of the [CrSe2 ] ∞ layer bear a spin S = 3/2, which orders below T_N = 55 K. Here we report low temperature inelastic neutron scattering experiments on AgCrSe2, alongside the magnetic field evolution of its thermal and electrical transport. We observe a very low frequency mode at 3 meV, ascribed to large anharmonic displacements of the Ag+ ions in the [Ag] ∞ layer, and 2D magnetic fluctuations up to 3 T_N in the chromium layer. The low thermal conductivity of AgCrSe2 is attributed to acoustic phonon scattering by a regular lattice of Ag + oscillating in quasi-2D potential wells. These findings highlight a new way to achieve localised phonon modes in a perfectly crystalline solid.
Fichier principal
Vignette du fichier
srep23415.pdf (1.26 Mo) Télécharger le fichier
Origin : Publisher files allowed on an open archive

Dates and versions

hal-02184747 , version 1 (01-03-2024)

Identifiers

Cite

F. Damay, S. Petit, S. Rols, M. Braendlein, R. Daou, et al.. Localised Ag+ vibrations at the origin of ultralow thermal conductivity in layered thermoelectric AgCrSe2. Scientific Reports, 2016, 6, pp.23415. ⟨10.1038/srep23415⟩. ⟨hal-02184747⟩
68 View
3 Download

Altmetric

Share

Gmail Facebook X LinkedIn More