Theoretical evaluation of the thermal conductivity in framework (clathrate) semiconductors

J. Dong, O. F. Sankey, C. W. Myles, G. K. Ramachandran, P. F. McMillan, J. Gryko

Research output: Contribution to journalConference articlepeer-review

Abstract

We have calculated the room temperature thermal conductivity in semiconductor germanium clathrates using statistical linear-response theory and an equilibrium molecular dynamics (MD) approach. A key step in our study is to compute a realistic heat-current J (t) and a corresponding auto-correlation function < J (t) J (0) >. To ensure convergence of our results and to minimize statistical fluctuations in our calculations, we have constructed large super-cell models (2944 atoms) and have performed several independent long time simulations (<1,500 ps in each simulation). Our results show an unexpected "oscillator" character in the heat-current correlation function of the guest-free Ge clathrate frameworks. This is absent in the denser diamond phase and other with simple structural frameworks. We seek to interpret these results using lattice dynamics information. A study of the effects of the so-called "rattling" guest atoms in the open-framework clathrate materials is in progress.

Original languageEnglish
Pages (from-to)Z611-Z616
JournalProceedings - IEEE International Symposium on Circuits and Systems
Volume4
StatePublished - 2001
EventIEEE International Symposium on Circuits and Systems (ISCAS 2001) - Sydney, NSW, Australia
Duration: May 6 2001May 9 2001

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