籠狀化合物由於它們的結構，被期待著具有好的熱電特性。多面體籠子內填充著鹼土族原子，由於鹼土族原子在籠子內振動，造成聲子散射，降低晶格熱導率，以其達到較高的ZT值。
本篇論文研究的是Ba8Ga16-xSi30+x (x= -1,0,1) and Ba8-yGa16S30 (y= 0,1,2) 一系列的籠形化合物。這些樣品由電弧熔融arc melting技術來製備; 為了得知是否摻雜在正確的位置，再經由x-ray 散射得知結構。結構正確後，測量其電阻值、熱傳導率、Seebeck coefficient。
我們發現Ba8Ga16Si30在室溫(T=300 K)擁有最高的ZT值 0.06。並估計900 K時Ba8Ga17Si29 的 ZT值大約為1.01 高於 Ba8Ga16Si30的ZT=0.89，因為Ba8Ga17Si29在高溫時具有較高的Seebeck coefficient 及較低的電阻率。

Clathrate compounds are expected to have good thermoelectric property; because of their structure. The guest atoms are included in the host cages. Because of weak interaction between the guest and framework atoms, rattling motion can make the lattice thermal conductivity lower, so it may have higher figure-of-merit, ZT.
This paper is for Ba8Ga16-xSi30+x (x= -1,0,1) and Ba8-yGa16S30 (y=0,1,2) clathrate compounds. They are prepared by arc-melting and characterized for their structure by x-ray diffraction, electrical resistivity, Seebeck coefficient and thermal conductivity measurements.
It is found that the Ba8Ga16Si30 has the biggest ZT=0.06 in room temperature (T=300 K). We estimated that Ba8Ga17Si29 has ZT=1.01 at T=900 K bigger than Ba8Ga16Si30 whose ZT is 0.89 at the same temperature, because Ba8Ga17Si29 has a higher Seebeck coefficient and a lower electrical resistivity.

1.Z.H. Dughaish, “Lead telluride as a thermoelectric material for thermoelectric power generation” Physica B. 322, 205(2002).
2.Mercouri G. Kanatzidis, Chem. Mater. 22 ,648 (2010).
3.V. L. Kuznetsov, L. A. Kuznetsova, A. E. Kaliazin, and D. M. Rowe, J. Appl. Phys. 87, 7871 (2000) .
4.Liyan Qiu, Ian P. Swainson, George S. Nolas,and Mary Anne White, Physical Review B. 70, 035208 (2004).
5.C.Kittle, Introduction to Solid State Physics, 8th ed. New York. Wiley,Ch4-6.(1996).
6.Shang-Feng Weng, “Chemical pressure effect on the thermoelectric properties of SrSi2”, NCKU, Department of Physics . (2012).
7. Wen-Shin Sun, “Study of Nb substitution on the thermoelectric properties of Fe2VGa”,NCKU, Department of Physics . (2010).
8.Devaraj Nataraj, Jiro Nagao, Marhoun Ferhat, and Takao Ebinuma，J. Appl. Phys. 93, 2424 (2003).
9.Joseph R. Sootsman, Duck Young Chung, and Mercouri G. Kanatzidis, Angew. Chem. Int. Ed. 48, 8616 (2009).
10.Marion C. Schäfer, Yuki Yamasaki, Veronika Fritsch , and Svilen Bobev, Crystals, 1, 145, (2011).
11.Deng Shukang,Tang Xinfeng,Xiong Cong,and Zhang Qingjie, 28,4 (2007)
12.R Shirataki, M Hokazono, T Nakabayashi and H Anno, IOPscience.18, 142001
13.J. L. Cohn, G. S. Nolas, V. Fessatidis, T. H. Metcalf, and G. A. Slack, Physical Review Letters. 82, 779 (1999).
14.Eric S. Toberer, M. Christensen, B. B. Iversen, and G. Jeffrey Snyder, Physical Review B. 77, 075203 (2008).
15.A. Saramat, G. Svensson, A. E. Palmqvist, C. Stiewe, E. Mueller et al. , J. Appl. Phys. 99,023708(2006).
16.G. S. Nolas, J.-M. Ward and J. Gryko, L. Qiu and M. A. White, Phys. Rev. B.64, 153201 (2001 ) .
17.G. S. Nolas and C. A. Kendziora, Phys. Rev. B.62, 7157 (2000 ) .
18.G. S. Nolas, T. J. R. Weakly, J. L. Cohn, and R. Sharma, Phys. Rev. B. 61,
3845 (2000 ) .
19.R. F. W. Herrmann, K. Tanigaki, T. Kawaguchi, S. Kuroshima, and O.
Zhou, Phys. Rev. B .60, 13245 (1999 ) .
20.B.C. Sales, R.J. Chakoumakos, J.R. Thompson, D. Mandrus, Phys. Rev. B.63,245113 (2001).
21.Tetsuji Kawaguchi, Katsumi Tanigaki, and Masahiro Yasukawa, Appl. Phys. Lett. 77, 3438 (2000).
22.S. B. Schujman, G. S. Nolas, R. A. Young, C. Lind, A. P. Wilkinson et al. J. Appl. Phys. 87, 1529 (2000 ).
23.A. Bentien, B. B. Iversen, J. D. Bryan, G. D. Stucky, A. E. C. Palmqvist et al. J. Appl. Phys. 91, 5694 (2002).
24.C. Candolfi, U. Aydemir, M. Baitinger, N. Oeschler, F. Steglich, and Yu . Grin, J. Appl. Phys. 111, 043706 (2012).
25.J. D. Bryan, V. I. Srdanov, and G. D. Stucky, D. Schmidt, Phys. Rev. B .60, 3064 (1999).
26.A. Bentien, M. Christensen, J. D. Bryan, A. Sanchez, S. Paschen, F. Steglich, G. D. Stucky, and B. B. Iversen, Phys. Rev. B. 69, 045107 (2004).
27.K. Suekuni, M. A. Avila, K. Umeo, and T. Takabatake, Phys. Rev. B. 75,195210 (2007)
28.M. Falmbigl, G. Rogl, P. Rogl, M. Kriegisch, H. Mu¨ller, E. Bauer, M. Reinecker, and W. Schranz,J. Appl. Phys. 108, 043529 (2010)
29.I. Zeiringer, E. Bauer, A. Grytsiv, P. Rogl, and H. Effenberger, Jpn. J.
Appl. Phys. 50, 05FA01 (2011).
30.N. Melnychenko-Koblyuk, A. Grytsiv, P. Rogl, G. Giester, St. Berger, H.
Kaldarar, G. Durand, H. Michor, F. Ro¨hrbacher, M. Koza, E. Royanian, E.
Bauer, M. Rotter, and H. J. Schmid: J. Phys.: Condens. Matter. 19
046203(2007).
31.B. C. Chakoumakos, B. C. Sales, D. G. Mandrus, and G. S. Nolas, J.
Alloys Compd. 296, 80 (2000) .
32.N. P. Blake, D. Bryan, S. Latturner, L. Mo ” llnitz, G. D. Stucky, and H.
Metiu, J. Chem. Phys. 114, 10063 (2001 ).
33.N. P. Blake, D. Bryan, S. Latturner, G. D. Stucky, and H. Metiu. J. Chem.
Phys. 115, 8060 (2001)
34.L. T. K. Nguyen, U. Aydemir, M. Baitinger, E. Bauer, H. Borrmann,
U. Burkhardt, J. Custers, A. Haghighirad, R. Ho¨fler, K. D. Luther, et al.,
Dalton Trans. 39, 1071 (2010)
35.U. Aydemir, C. Candolfi, A. Ormeci, Y. Oztan, M. Baitinger, N. Oeschler,
F. Steglich, and Yu. Grin, Phys. Rev. B. 84, 195137 (2011)
36.N. Jaussaud, P. Gravereau, S. Pechev, B. Chevalier, M. Me´ne´trier, P. Dordor,R. Decourt, G. Goglio, C. Cros, and M. Pouchard,C. R. Chim. 8, 39 (2005).
37.J. Xu, J. Tung, K. Sato, Y. Tanabe, H. Miyasaka, M. Yamashita, S. Heguri,
and K. Tanigaki, Phys. Rev. B. 82, 085206 (2010).
38.T. Mori, K. Iwamoto, S. Kushibiki, H. Honda, H. Matsumoto, N. Toyota,
M. A. Avila, K. Suekuni, and T. Takabatake, Phys. Rev. Lett. 106, 015501
(2011).
39.K. Suekuni, M. A. Avila, K. Umeo, H. Fukuoka, S. Yamanaka, T. Nakagawa, and T. Takabatake, Phys. Rev. B. 77, 235119 (2008).
40.M. A. Avila, K. Suekuni, K. Umeo, H. Fukuoka, S. Yamanaka, and T.
Takabatake, Appl. Phys. Lett. 92, 041901 (2008).
41.N. Tsujii, J. H. Roudebush, A. Zevalkink, C. A. Cox-Uvarov, G. J. Snyder,
and S. M. Kauzlarich,J. Solid State Chem. 184, 1293 (2011).
42.Deng Shu-Kang , Tang Xin-Feng , and Tang Run-Sheng, Chinese Phys. B . 18 3084 (2009).