4-8 July 2016
Kramer Law building
Africa/Johannesburg timezone
Paper Review: Initial screening in progress
Home > Timetable > Session details > Contribution details
PDF | XML | iCal

Lattice thermal conductivity properties of three binary type- I Sn clathrates from Density Functional Theory

Presented by Mr. Peter EGBELE on 5 Jul 2016 from 14:00 to 14:20
Type: Oral Presentation
Track: Track G - Theoretical and Computational Physics

Abstract

A low thermal conductivity material is a good choice for a thermoelement provided the power factor is not affected adversely. In this study, the suppression of thermal conductivity, using the high temperature phase in the three binary type-I Sn clathrates, Cs8Sn44, K8Sn44 and Rb8Sn44 was studied using Density Functional Theory in the Local Density approximation. Analysis of the projected density of state suggests a decoupled oscillations of the guest atoms which is believed to scatter the acoustic phonons and hence reduce the lattice thermal conductivity [1]. Using ab initio molecular dynamics phonon calculations, an indication of any anharmonicity was investigated. Our result is confirmed by a detailed analysis of the lattice vibrations and the role the guest atoms play in reducing the lattice thermal conductivity from similar studies using Raman spectroscopy and inelastic neutron scattering [2]. [1] Voneshen, D. J., Refson, K., Borissenko, E., Krisch, M., Bosak, A., Piovano, A., ... & Roger, M. (2013). Suppression of thermal conductivity by rattling modes in thermoelectric sodium cobaltate. Nature materials, 12(11), 1028-1032. 2] Christensen, Mogens, Fanni Juranyi, and Bo B. Iversen. "The rattler effect in thermoelectric clathrates studied by inelastic neutron scattering." Physica B: Condensed Matter 385 (2006): 505-507.

Award

Yes

Level

PhD

Supervisor

Prof. Daniel P Joubert [daniel.joubert2@wits.ac.za ] University Of Witwatersrand, Johannesburg

Paper

Yes

Permission

Yes

Place

Location: Kramer Law building
Address: UCT Middle Campus Cape Town
Room: 4A


Primary authors

More

Co-authors

More