Heusler-type Ru2TaAl我們利用量測其電阻、熱電、熱導、比熱和核磁共振來得知其傳輸性質和電子特性，並利用第一原理理論計算去驗證我們的實驗結果。
利用電弧法將樣品成功合成，必在800℃下退火72小時，從XRD粉末繞射圖來看確認其為 Cubic L21 結構，測量電阻得知其有半金屬的特性，測量Seebeck得知其主要傳輸載子為電洞，測量比熱去計算出在費米能階上有殘餘的態密度，再從自旋晶格鬆弛時間在高溫表現的行為推測為傳輸載子受到熱激發跨越鷹能隙並計算出能隙大小，從熱導推測此樣品是一個有潛力的熱電材料，最後藉由第一原理的理論計算驗證上述實

In principle, a Heusler compound with cubic L21 structure having total number of valence electrons per formula unit (VEC) equal to twenty-four possesses a band gap or pseudogap in the vicinity of the Fermi level. The present case of Ru2TaAl also belongs to the member of VEC = 24 family. To further examine the possible gap of pseudogap features in Ru2TaAl, Ru2TaAl ingots were prepared by using an ordinary arc-melting technique. The X-ray diffraction pattern (XRD) result confirms the L21 structure with a lattice constant a = 6.13 Å. we have carried out the transport, thermoelectric, specific heat, and 27Al NMR measurements to crystallize its physical properties. Temperature-dependent electrical resistivity ρ(T), exhibits semiconducting behavior as indicated by its negative temperature coefficient of resistivity. The Seebeck coefficient S is positive in the entire temperature range under investigate, suggesting that the dominant carriers for the thermoelectric transport are holes in Ru2TaAl. A small value of the Fermi level DOS N(EF) was estimated according to Low-T specific heat. From the analysis of NMR 1/T1, we obtained a reliable pseudogap of about 0.29 eV for Ru2TaAl.All measured quantities are in good agreement with the semimetallic scenario, implying that Ru2TaAl is a semimetal with a pseudogap at around the Fermi level.

[1] T. Graf, C. Felser, and S. S. P. Parkin, Progress in Solid State Chemistry 39, 1(2011), and references therein.
[2] M. Weinert, R. E. Watson, Hybridization-induced band gaps in transition-metal aluminides, Phys. Rev. B, 58(1998).
[3] A. Bansil, S. Kaprzyk, P. E. Mijnarends, and J. Toboła, Phys. Rev. B 60, 13396 (1999).
[4] A. Kellou, N. E. Fenineche, T. Grosdidier, H. Aourag, and C. Coddet, Journal of Applied Physics 94, 3292 (2003)
[5] I. Galanakis, P. H. Dederichs, and N. Papanikolaou Phys. Rev. B 66, 174429 (2002).
[6] Y. Nishino, M. Kato, S. Asano, K. Soda, M. Hayasaki, and U. Mizutani, Phys. Rev. Lett. 79, 1909(1997).
[7] C. S. Lue and J. H. Ross, Jr., Phys. Rev. B 58, 9763 (1998).
[8] C. S. Lue and J. H. Ross, Jr., C. F. Chang, H. D. Yang, Phys. Rev. B 60, R13941 (1999).
[9] C. S. Lue and J. H. Ross, Jr., Phys. Rev. B 63, 054420 (2001).
[10] C. S. Lue, Yang Li, Joseph H. Ross, Jr., and George M. Irwin, Phys. Rev. B 67, 224425 (2003).
[11] A. Slebarski and J. Goraus, Phys. Rev. B 80, 235121 (2009).
[12] C. S. Lue and J. H. Ross, Jr., K. D. D. Rathnayaka, D. G. Naugle, S. Y. Wu, and W. –H. Li, J. Phts.: Conden. Matter 13, 1585 (2001).
[13] A. Slebarski, M. B. Maple, E. J. Freeman, C. Sirvent, D. Tworuszka, and M. orzechowska, A. Wrona, A. Jezierski, S. Chiuzbaian, and M. Neumann, Phys. Rev. B 62, 3296 (2000).
[14] A. Slebarski, J. Deniszczyk, W. Borgiel, A. Jezierski, M. Swatek, A. Winiarska, M. B. Maple, and W. M. Yuhasz, Phys. Rev. B 69, 155118 (2004).
[15] I. Galanakis, J. Phys.: Condens. Matter 16, 3089 (2004).
[16] S. Skaftouros, K. Ozdogan, E. Sasioglu, and I. Galanakis, Phys. Rev. B 87, 024420 (2013).
[17] Y. Nishino, H. Kato, M. Kato, and U. Mizutani, Phys. Rev. B 63, 233303 (2001).
[18] C. S. Lue and Y. -K. Kuo, Jr., Phys. Rev. B 66, 085121 (2002).
[19] M. Vasundhara, V. Srinivas, and V. V. Rao, J. Phys.: Condens. Matter 17, 6025 (2005).
[20] Y. Nishino, S. Deguchi, and U. Mizutani, Phys. Rev. B 74, 115115 (2006).
[21] M. Vasundhara, V. Srinivas, and V. V. Rao, Phys. Rev. B 77, 224415 (2008).
[22] M. Mikami, Y. Kinemuchi, K. Ozaki, Y. Terazawa, and T. Takeuchi, J. Appl. Phys. 111, 09371 0 (2012).
[23] Y. Nishino, and Y. Tamada, J. Appl. Phys. 115, 123707 (2014).
[24] D. I. Blic, G. Hautier, D. Waroquiers, G. –M. Rignanese, and P. Ghosez, Phys Rev. Lett. 114, 136601 (2015).
[25] H. Al-Yamani and B. Hamad, J. Electron. Mater. 45, 1101 (2016).
[26] Q. Feng, T. K. Nandy, and T. M. Pollock, Scripta. Mater. 50, 849 (2004).
[27] 李雅明,固態電子學,全華科技圖書股份有限公司,(1995).
[28] Charles Kittel,Introduction to solid state physics, John Wileyy and sins(1986)
[29] 賴耿陽,核磁共振的基礎,復漢出版社,第二章(1991).
[30] T.Asada and K,Terakura,J.Phys.F:M.Phys 12 1387(1982).
[31] C. S. Lue and Y. -K. Kuo, J. Appl. Phys. 96, 2681 (2004).
[32] C. S. Lue and Y. -K. Kuo, S. –N. Horng, S. Y. Peng, and C. Cheng, Phys. Rev. B 71, 064202 (2005).
[33] C. S. Lue, C. F. Chen, J. Y. Lin, Y. T. Yu, and Y. –K. Kuo, Phys. Rev. B 75, 064204 (2007).
[34] M. Yin and P. Nash, J. Alloys Comp. 634, 70 (2015).
[35] C. N. Kuo, H. W. Lee, C. –M. Wei, Y. H. Lin, Y. K. Kuo, and C. S. Lue, Phys. Rev. B 94, 205116 (2016).
[36] C. S. Lue, W. J. Lai, C. C. Chen, and Y. –K. Kuo, J. Phys.: Condens. Matter 16, 4283 (2004).
[37] C. S. Lue, J. W. Huang, D. S. Tsai, K. M. Sivakumar, and Y. –K. Kuo, J. Phy.: Condens. Matter 20, 255233 (2008).
[38] C. S. Lue, M. D. Chou, N. Kaurav, Y. T. Chung, and Y. K. Kuo, Appl. Phys. Lett. 94, 192105 (2009).
[39] C. S. Lue, Y. S. Tseng, J. Y. huang, H. L. Hsieh, H. Y. Liao, and Y. K. Kuo, AIP Advance 3, 072132 (2013).
[40] Y. K. Kuo, B. Ramachandran, and C. S. Lue, Frontiers in Chemistry, Inorganic Chemistry 2, 106 (2014).
[41] Jurgen Winterlik, Gerhard H. Fecher, and Claudia Felser, Phys B 78, 184506 (2008).
[42] C. Wan, Y. Wang, N. Wang, W. Norimatsu, M. Kusunoki, and K. Kumoto, Sci. Technol. Adv. Mater., 11, 044306 (2010).
[43] F. S. Rocha, G.L.F. Fraga, D. E. Brandao, C. M. da Silva, A. A. Gomes, Phys B 269 (1999).
[44] M. A. S. Boff, G. L. Fraga, D. E. Brandao, A. A. Gomes, and T. A. Grand, Phys. Stat. sol. 154, 549 (1996).
[45] J. Korringa, Physica 16, 601 (1950).
[46] 核磁共振量測物質的微觀電磁性質文/呂欽山、賴文振，物理雙月刊(26卷3期)(2004).
[47] C.S.Lue,A Nuclear magnetic resonance probe of Fe-V-Al intermetallics(1999).
[48] C. S. Lue, S. Y. Wang, and C. P. Fang, Phys. B 75, 235111 (2007).
[49] C. P. fang, C. S. Lue. And B. –L. Young, Phys. Rev. B 83, 113105 (2011).
[50] C. S. Lue, S. Chepin, James Chepin, and J. H. Ross, Jr., Phys. Rev. B 57, 7010 (1998).
[51] C. S. Lue, B. X. Xie, S. N. Horng, J. H. Su, and J. Y. Lin, Phys, Rev. B 71. 195104 (2005).
[52] C. S. Lue, J. Y. Lin, and B. X. Xie, Phys. Rev. B 73, 035125 (2006).
[53] C. S. Lue, B. X. Xie, C. P. Fang, Phys. B 74, 014505 (2006).
[54] C.S.Lue,dissertation of doctor of philosophy,Texas A&M University(1991).
[55] C. S. Lue and J. H. Ross, Jr., Phys. Rev. B 61, 9863 (2000).
[56] M. Shishkin and G. Kresse, Phys. Rev. B 75, 235102 (2007).
[57] J. P. Perdew, K. Burke, and M. Ernzerhof, Phys. Rev. Lett. 77, 3865 (1996).