Department of Physics, University of South Florida, Tampa, Florida, USA.
Phys Rev Lett. 2010 Jan 8;104(1):018301. doi: 10.1103/PhysRevLett.104.018301.
The observation of intrinsic structural, electrical, and thermal properties from measurements on single-crystal specimens of clathrate-II Na24Si136 is reported, revealing metallic conduction in agreement with electronic structure calculations. Low-temperature heat capacity measurements corroborate a substantial electronic density of states at the Fermi level, and reveal an Einstein-like mode that can be attributed to Na guest "rattling". The large thermal conductivity of Na24Si136, compared to literature data for other intermetallic clathrates, can be understood in terms of the predominant electronic contribution for the fully filled Na24Si136 composition.
本文报道了对笼型-II Na24Si136 单晶样品进行的内在结构、电学和热性能测量的结果，这些结果表明其具有金属导电性，与电子结构计算结果一致。低温热容测量证实费米能级附近存在大量的电子态密度，并揭示了一种爱因斯坦模式，可以归因于 Na 客体的“颤动”。与其他金属间笼型化合物的文献数据相比，Na24Si136 的高热导率可以用完全填充的 Na24Si136 组成的主要电子贡献来解释。
