Speaker
Apply to be<br> considered for a student <br> award (Yes / No)?
No
Level for award<br> (Hons, MSc, <br> PhD)?
No
Would you like to <br> submit a short paper <br> for the Conference <br> Proceedings (Yes / No)?
No
Main supervisor (name and email)<br>and his / her institution
Prof. Daniel Joubert (daniel.joubert@wits.ac.za)
Abstract content <br> (Max 300 words)<br><a href="http://events.saip.org.za/getFile.py/access?resId=0&materialId=0&confId=34" target="_blank">Formatting &<br>Special chars</a>
In a recent study, we reported an unusual quasielastic inelastic neutron scattering (INS) signal in the K analogue of the Al-doped series of cage compounds with the β-pyrochlore structure, AAl0.33W1.67O6 (A = K, Rb, Cs) [1]. We are studying this family of compounds because the rattling modes of the alkali metal atoms [2, 3] are similar to those found to enhance thermoelectric performance in both clathrates [4] and skutterudites [5]. This talk will discuss our recent thermal conductivity [6] and specific heat data in terms of the vibrational density of states calculated from ab initio molecular dynamics (MD) simulations validated against experimental INS spectra and show the significance of the novel K dynamics for these properties. I will conclude with a tentative sketch of the prospects of these compounds for thermoelectric development.
References
[1] E. Shoko, G. J. Kearley, V. K. Peterson, H. Mutka, M. M. Koza, J.-I. Yamaura, Z. Hiroi, G. J. Thorogood, submitted to Phys. Rev. B, ( arXiv:1310.8137).
[2] K. Oshiba and T. Hotta, J. Phys. Soc. Jpn. 80, 094712 (2011).
[3] J. Yamaura and Z. Hiroi, J. Phys. Soc. Jpn. 80, 054601 (2011), Z. Hiroi, J.-I. Yamaura and K. Hattori, J. Phys. Soc. Jpn. 81, 11012 (2012).
[4] B. C. Sales, B. C. Chakoumakos, R. Jin, J. R. Thompson and D. Mandrus, Phys. Rev. B 63, 245113
(2001).
[5] M. M. Koza, M. R. Johnson, R. Viennois, H. Mutka, L. Girard and D. Ravot, Nature Mater. 7, 805 (2008).
[6] E. Shoko, V. K. Peterson, and G. J. Kearley, J. Appl. Phys. 115, 033703, (arXiv:1310.8382v2)
