“Glass-like” thermal conductivity gradually induced in thermoelectric Sr8Ga16Ge30 clathrate by off-centered guest atoms

Simple item page
dc.contributor.authorChristensen, Sen_AU
dc.contributor.authorSchmøkel, MSen_AU
dc.contributor.authorBorup, KAen_AU
dc.contributor.authorMadsen, GKHen_AU
dc.contributor.authorMcIntyre, GJen_AU
dc.contributor.authorCapelli, SCen_AU
dc.contributor.authorChristensen, Men_AU
dc.contributor.authorIversen, BBen_AU
dc.date.accessioned2021-12-17T03:25:25Zen_AU
dc.date.available2021-12-17T03:25:25Zen_AU
dc.date.issued2016-05-10en_AU
dc.date.statistics2021-12-07en_AU
dc.description.abstractThe origin of the “glass-like” plateau in thermal conductivity of inorganic type I clathrates has been debated for more than a decade. Here, it is demonstrated that the low temperature thermal conductivity of Sr8Ga16Ge30 can be controlled by the synthesis method: A flux-grown sample has a “glass-like” plateau in thermal conductivity at low temperature, while a zone-melted sample instead has a crystalline peak. A combination of flux-growth and zone-melting produces an intermediate thermal conductivity. In a comprehensive study of three single crystal samples, it is shown by neutron diffraction that the transition from crystalline peak to “glass-like” plateau is related to an increase in Sr guest atom off-centering distance from 0.24 Å to 0.43 Å. By modifying ab initio calculated force constants for the guest atom to an isotropic model, we reproduce both measured heat capacity and inelastic neutron scattering data. The transition from peak to plateau in the thermal conductivity can be modeled by a combined increase of Rayleigh and disorder scattering. Measurement of heat capacity refutes simple models for tunneling of Sr between off-center sites. Furthermore, the electronic properties of the same samples are characterized by Hall carrier density, Seebeck coefficient, and resistivity. The present comprehensive analysis excludes tunneling and charge carrier scattering as dominant contributors to the “glass-like” plateau. The increased guest atom off-centering distance controlled by synthesis provides a possible microscopic mechanism for reducing the low temperature thermal conductivity of clathrates. © 2021 AIP Publishing LLC.en_AU
dc.identifier.articlenumber185102en_AU
dc.identifier.citationChristensen, S., Schmøkel, M. S., Borup, K. A., Madsen, G. K. H., McIntyre, G. J., Capelli, S. C., Christensen, M., & Iversen, B. B. (2016). “Glass-like” thermal conductivity gradually induced in thermoelectric Sr8Ga16Ge30 clathrate by off-centered guest atoms. Journal of Applied Physics, 119, 185102. doi:10.1063/1.4948334en_AU
dc.identifier.issn1089-7550en_AU
dc.identifier.journaltitleJournal of Applied Physicsen_AU
dc.identifier.urihttps://doi.org/10.1063/1.4948334en_AU
dc.identifier.urihttps://apo.ansto.gov.au/dspace/handle/10238/12544en_AU
dc.identifier.volume119en_AU
dc.language.isoenen_AU
dc.publisherAIP Publishingen_AU
dc.subjectThermal conductivityen_AU
dc.subjectTemperature range 0065-0273 Ken_AU
dc.subjectNeutron diffractionen_AU
dc.subjectInelastic scatteringen_AU
dc.subjectSpecific heaten_AU
dc.subjectElectrical propertiesen_AU
dc.subjectSeebeck effecten_AU
dc.subjectClathratesen_AU
dc.title“Glass-like” thermal conductivity gradually induced in thermoelectric Sr8Ga16Ge30 clathrate by off-centered guest atomsen_AU
dc.typeJournal Articleen_AU
Files
License bundle
Now showing 1 - 1 of 1
Thumbnail Image
Name:
license.txt
Size:
1.63 KB
Format:
Item-specific license agreed upon to submission
Description:
Download
Collections
Journal Articles