## 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 language | English |
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Pages (from-to) | Z611-Z616 |

Journal | Proceedings - IEEE International Symposium on Circuits and Systems |

Volume | 4 |

State | Published - 2001 |

Event | IEEE International Symposium on Circuits and Systems (ISCAS 2001) - Sydney, NSW, Australia Duration: May 6 2001 → May 9 2001 |