Disorder-driven glasslike thermal conductivity in colusite Cu<sub>26</sub>V<sub>2</sub>Sn<sub>6</sub>S<sub>32</sub> investigated by Mössbauer spectroscopy and inelastic neutron scattering - Archive ouverte HAL Access content directly
Journal Articles Physical Review Materials Year : 2020

Disorder-driven glasslike thermal conductivity in colusite Cu26V2Sn6S32 investigated by Mössbauer spectroscopy and inelastic neutron scattering

Gérard Le Caër
Pierric Lemoine

Abstract

The influence of structural disorder on the thermal transport in the colusite Cu26V2Sn6S32 has been investigated by means of low-temperature thermal conductivity and specific heat measurements (2–300 K), 119Sn Mössbauer spectroscopy and temperature-dependent powder inelastic neutron scattering (INS). Variations in the high-temperature synthesis conditions act as a key parameter for tuning the degree of disorder in colusite compounds. Intriguingly, we find that all synthesized samples are disordered, the degree of which varies with the synthesis conditions used. Mössbauer data clearly evidence that Sn atoms do not solely occupy the 6c site of the crystal lattice but are present on possibly both the Cu and V sites, leading to a random distribution of these three cations within the unit cell. Increasing the disorder in these materials tends to lead to a smearing out of the main features in the phonon density of states measured by INS. Although the evolution of the inelastic signal upon warming is well described by a quasiharmonic approximation, elastic properties calculations indicate large average Grüneisen parameters, consistent with those determined experimentally from thermodynamic data. Increasing the level of disorder results in a decreased average Grüneisen parameter suggesting that the lowered lattice thermal conductivity is not driven by enhanced anharmonicity. These results provide experimental evidence to support that the remarkable changeover in the lattice thermal conductivity from crystalline to glasslike is solely driven by enhanced disorder accompanied by local lattice distortions.
Fichier principal
Vignette du fichier
Candolfi et al-2020-Disorder-driven glasslike thermal conductivity in colusite.pdf (1.51 Mo) Télécharger le fichier
Origin : Files produced by the author(s)
Loading...

Dates and versions

hal-02507469 , version 1 (12-05-2020)

Identifiers

Cite

Christophe Candolfi, Gabin Guélou, Cédric Bourgès, Andrew Supka, Rabih Al Rahal Al Orabi, et al.. Disorder-driven glasslike thermal conductivity in colusite Cu26V2Sn6S32 investigated by Mössbauer spectroscopy and inelastic neutron scattering. Physical Review Materials, 2020, 4 (2), pp.025404. ⟨10.1103/PhysRevMaterials.4.025404⟩. ⟨hal-02507469⟩
106 View
101 Download

Altmetric

Share

Gmail Facebook Twitter LinkedIn More