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Direct observation of atomic motion in a nano-scale cage (Press Release)

Release Date
10 Mar, 2008
  • BL09XU (Nuclear Resonant Scattering)
  • BL35XU (High Resolution lnelastic Scattering)

Atomic motion in a nano-scale-cage, is an important issue relating to the discovery of new thermoelectric materials.  Previous works suggested that the atoms in such cages vibrate freely (like beans in a rattle) without affecting the motion of the cage atoms, and that such a vibration might scatter the acoustic modes that carry heat.  This mechanism could then be responsible for reducing the thermal conductivity of cage compounds, such as the skutterudites shown in Fig. 1, improving their thermoelectric behavior.

The present work combined two different methods of inelastic scattering to show that this is not the case: that the motion of the atom inside the cage in fact affects the acoustic modes in a filled skutterudite.  This gives some impetus to develop a new understanding of thermoelectric materials. 


Fig. 1. Crystal structure of a filled skutterudite SmRu4P12.Fig. 1. Crystal structure of a filled skutterudite SmRu4P12.

"Direct Observation of Low-Energy Sm Phonon in SmRu4P12"
Satoshi Tsutsui, Hisao Kobayashi, Daisuke Ishikawa, John P. Sutter, Alfred Q. R. Baron, Takumi Hasegawa, Norio Ogita, Masayuki Udagawa, Yoshitaka Yoda, Hideya Onodera, Daisuke Kikuchi, Hitoshi Sugawara, Chihiro Sekine, Ichimin Shirotani, and Hideyuki Sato
Journal of the Physical Society of Japan Vol. 77 No. 3, March, 2008

For more information, please contact Dr. Satoshi Tsutsui (JASRI/SPring-8):
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