摘要

本實驗藉由第一原理分析CoSi(核)/SiO2(殼)、CrSi2 (核)/SiO2 (殼)和 FeSi(核)/SiO2 (殼)奈米電纜異常的鐵磁性質，這是有別於它們在塊材時為反磁性以及順磁性材料的。這樣的奈米電纜結構，主要是因為表面的過渡金屬原子未完全配位鍵結及鍵結的扭曲，使得過渡金屬原子3d軌域的自旋向上和自旋向下的電子數不同，而有鐵磁性材料的性質。藉由高解析度電子顯微鏡圖來確定其成長方向和朝向界面的方向，以朝向界面的方向的過渡金屬矽化物和非晶質SiO2接合，建構近似真實奈米電纜的表面結構，並利用第一原理模擬分析。CoSi奈米線為B20型態結構(空間族為P213)，其沿著[211]方向成長，CoSi奈米線除了表面鍵結得不對稱性產生磁性外，內部的缺陷也會產生磁化量，藉由近一步的缺陷假設計算，將內部缺陷產生的磁化量分配到表面Co原子，計算結果和實驗結果相近； CrSi2奈米線為C40型態結構(空間族為P6222)，其沿著[0001]方向成長，CrSi2奈米線磁化量來自於表面不對稱鍵結，第一原理計算出的值在加上表面粗糙度所增加的表面積以及氧的影響，計算結果得出和實驗結果相同數量級的磁化量；FeSi奈米線為B20型態結構(空間族為P213)，其沿著[111]方向成長FeSi奈米線磁化量也是來自於表面不對稱鍵結，由於上下界面Fe原子距離表面差異大，使的磁化量差距大。了解過渡金屬矽化物奈米線的磁性來源，可以研究其在磁性半導體的應用。

First-principles density functional theory-based with spin-polarized calculations were used to investigate CoSi/SiO2 ,CrSi2/SiO2 and FeSi/SiO2 nanowires. The CoSi,CrSi2 and FeSi in bulk are diamagnetic and paramagnetic , but the ferromagnetism in CoSi/SiO2 ,CrSi2/SiO2 and FeSi/SiO2 nanowires was observed. Due to the distorted /dangling bonds in surface , the electron spin up and spin down in d-orbital from transitional metal atoms become asymmetric. Nanowires grows direction and side direction is determined by high resolution TEM and set side direction linking with amorphous SiO2 to bulid a close nanowire surface structure to simulate by first-principle. The cubic CoSi B20 type (P213) nanowires grow along [211] direction. Magnetization is not only from Co atom in surface , but also caused by internal defect. Set the defect in CoSi to simulate and assign total internal magnetization to the surface Co atom, simulation value is pretty consistent with experimental result. The hexagonal CrSi2 C40 type (P6222) nanowires grows along [0001] direction. The ferromagnetism is caused by distorted/dangling bonds in surface. The simulations are very consistent with measurements by further considering the effects of interfacial roughness and distribution of oxygen around the interface. The cubic FeSi B20 type (P213) nanowires grow along [111] direction. The ferromagnetism is also caused by distorted/dangling bonds in surface. The distance from surface to up and down plane Fe atom is different largely, so the magnetization is different largely, too. To understand the ferromagnetism source in transitional metal silicides can investigate the application in ferromagnetic semiconductor.

[1] D. M. Brown, W. E. Engeler, M. Garfinkel, P. V. Gray, J. Electrochem.Soc., vol.115, p.874, 1968.
[2] P. Shah, IEEE Trans. Electron Devices, vol.26, p.631, 1979.
[3] K. L. Wang, T. C. Holloway, R. F. Pinizzotto, Z. P. Sobczak, W. R.Hunter, and A. F. Tash, Jr , IEEE Trans. Electron Device, vol.29, p.547, 1982.
[4]莊達人編著, “VLSI 製造技術”, 高立圖書有限公司 (1997).
[5]A. L. Schmitt, J. M. Higgins, J. R. Szczech, S. Jin, J. Mater. Chem. 20,223 (2010)
[6]E. Borisenko, Semiconducting silicides, Springer (2000)
[7]WTEC panel report on “ Nanostructure science and technology”, International Technology Research Institute, Dec. 1998, Maryland, USA.
[8] L.J. Chen , JOM, Vol.57, No.9, p24-31 2005.
[9] 陳力俊,“微電子材料與製程,”中國材料學會 2000.
[10] S. P.M Murarka Silicides for VLSI Application 1983
[11] H. Iwai, et al., Microelectronic Engineering 60, p. 157, 2002
[12] K. Seo, K. S. K. Varadwaj, P. Mohanty, S.Lee, Y. Jo, M. H. Jung, J. Kim, B Kim, Nano Lett., Vol. 7, No. 5, 2007 1240-1245
[13] Andrew L. Schmitt, Lei Zhu, Dieter Schmeiâer, F. J. Himpsel, Song Jin , J. Phys. Chem. B, Vol. 110, No. 37, 2006 18143
[14] J. R. Szczech, A. L. Schmitt, M. J. Bierman, S. Jin, Chem. Mater. 19, 3238 (2007)
[15] L. Ouyang, E. S. Thrall, M. M. Deshmukh, H. Park, Adv. Mater. 2006, 18, 1437–1440
[16]郭光宇等人，Ab initio study of novel magnetic materials in double perovskites structure
[17]中興大學材料工程學系碩士論文，探討氧化層對矽奈米線擴散機制之影響，鄭名廷，民國98年
[18]清華大學工程與系統科學系碩士論文，以第一原理分子動力學計算矽塊材與矽量子點之熔化溫度，陳立達，民國96年
[19]N. Manyala, Y. Sidis, J. F. Ditusa, G. Aeppli, D. P. Young, Z. Fisk, nature materials 3, 255 (2004)
[20]M. H. Ham, J. W. Lee, K. J. Moon, J. H. Choi, J. M. Myoung, J. Phys. Chem. C. 113, 8143 (2009)
[21]清華大學材料工程學系碩士論文，藉由第一原理分析
CrSi2(核)/SiO2(殼)奈米電纜異常鐵磁性質與氧化鎳薄膜成長研究，韓侑宏，民國99年
[1] 中興大學材料工程學系碩士論文，探討點接觸反應對矽化鎳奈米線異質結構形成機制與微結構之影響，許永瑞，民國98年
[2] 馮榮豐、陳錫添，奈米工程概論(2003)
[3] P. Yang, Y. Wu, and R. Fan, Int. J. Nanoscience, 1, 1, 2002
[4] A. M. Morales and C. M. Lieber, Science, 1998, 279, 208
[5] T.J. Trentler, K. M. Hickman, S. C. Goel, A.M. Viano, P. C. Gibbons and W. E. Buhro, Science 270, 1791 (1995)
[6] Younan Xia,Peidong Yang ,Adv.Mater.,(15), 353 (2003)
[7] H. Yu, W.E. Buhro, Advanced Materials 15 (5), 416 (2003) [8]B. T. Park, K. Yong, Nanotechnology 15, S365(2004)
[8]Dingman, S. D.; Rath, N. P.; Markowitz, P. D.; Gibbons, P. C.; Buhro, W. E. Angew. Chem. Int. Ed. 2000, 39, 1470.
[9] P. Yang and C.M. Lieber, J. Mater. Res. 12, 2981 (1997)
[10Z.X.Zhao,G..W.Meng,X.S.Peng,X.Y.Zhang,L.D.Zhang ,Appl.Phys.A,(74), 587 (2002)
[11] W. J. Strydom, J. C. Lombaard, R. Pretorius, Thin Solid Films, 131, 215 (1985)
[12]P. Crespo, R. Litran, T. C. Rojas, M. Multigner, J. M. de la Fuente, J. C. Sanchez-Lopez, M. A. Garcia, A. Hernando, S. Penades, A. Fernandez, Phys. Rev. Lett. 93, 087204 (1925)
[13]S. Lorenza, D. Fiorani, G. Scavia, P. Imperatori, Chem. Mater. 19, 1509 (2007)
[14] G. Kresse and J. Hafner, Phys. Rev. B 47, 558 (1993).
[15]清華大學材料工程學系碩士論文，藉由第一原理分析CrSi2(核)/SiO2(殼)奈米電纜異常鐵磁性質與氧化鎳薄膜成長研究，韓侑宏，民國99年
[16] K. Seo, K. S. K. Varadwaj, P. Mohanty, S. Lee, Y. Jo, M. H. Jung, J. Kim, B. Kim, Nano Lett. 7, 1240 (2007)
[17] A. E. van Arkel, J. H. Z. de Boer, Anorg. Allgem. Chem. 148, 345 (1925)
[18]P. Hohenberg and W. Kohn, Phys. Rev. 136 (1964) B864.
[19]W. Kohn and L. J. Sham, Phys. Rev. 140 (1965) A1133.
[20]J. P. Perdew, K. Burke, and M. Ernzerhof, Phys. Rev. Lett. 77 (1996) 3865.
[21]The Art of Molecular Dynamics Simulation, D. C. Rapaport.
[22]X. Zhao, D. Ceresoli, and D. Vanderbilt, Phys. Rev. B 71 (2005) 085107.
[23]D. R. Hamann, M. Schluter, and C. Chiang, Phy. Rev. Lett. 43 (1979) 1494.
[24]M. C. Payne, M. P. Teter, D. C. Allan, T. A. Arias, and J. D. Joannopoulos, Reviews of Modern Physics, Vol. 64, No. 4, 1045 (1992).
[25]F. S. Ham and B. Segall, Phys. Rev. 124 (1961) 1786.
[26]M. Methfessel, and M. Van Schilfgaarde, Phys. Rev. B, 48 (1993) 4937.
[27]G. A. Sai-Halasz, L. Esaki, and W. A. Harrison, Phys. Rev. B 18 (1978) 2812.
[28]Charles Kittel, Introduction to Solid State Physics, John Wiley and Sons (2005).
[29]The guide of VASP, can be retrieved from：http://cms.mpi.univie.ac.at/VASP/ , written by Georg Kresse and Jürgen Furthmüller.
[30]G. Kresse and J. Furthmuller, Phys. Rev. B 54 (1996) 11169.
[31]D. Vanderbilt, Phys. Rev. B, 41 (1990) 7892.
[32]C. G. Bmyden, Math. Comput 19 (155) 577.
[33]P. Pulay, Chem. Phys. Lett. 73 (1980) 393
[34]D. D. Johnson, Phys. Rev. B38, 12 (1988) 87.
[35]In general the Kohn-Sham energy functional for an ultrasoft (US) Vanderbilt pseudopotential (PP) can be written as [25-271].
[36]N. W. Ashcroft and N. D. Mermin, Solid state physics, Saunders College Publishing (1976).
[37]M. P. Marder, Condensed matter physics, John Wiley and Sons (2000).
[38]江進福, 物理雙月刊, 廿三卷五期, P549-553 (2001)
[39]L. H. Thomas, "The calculation of atomic fields". Mathematical Proceedings of the Cambridge Philosophical Society 23 (1927) 542.
[40]E. Fermi, "Un Metodo Statistico per la Determinazione di alcune Prioprietà dell'Atomo". Rend. Accad. Naz. Lincei 6 (1927) 602.
[41]E. Wigner, Transactions of the Faraday Society, 34 (1938) 0678.
[42]D. M. Ceperley and B. J. Alder, Phys. Rev. Lett. 45 (1980) 566.
[43]S. H. Vosko, J. P. Perdew, and A. H. Macdonald, Phy. Rev. Lett. 35 (1975) 1725.
[44]A. I. Liechtenstein, V. I. Anisimov, and J. Zaanen, Phys. Rev. B 52 (1995) R5467.
[45]G. Onida, L. Reining, and A. Rubio, Review of Modern Physics, vol. 74 (2002) 601.
[46]B. D. Cullity, Introduction to Magnetic Materials, Addison-Wesley Pub.Co. (1972).
[47]V. A. Krutov and L. N. Savushkin, J. Phys. A: Math. Nucl. Gen. 6 (1973) 93.
[48]Brant Fultz and James M. Howe, Transmission Electron Microscopy and Diffractometry of Materials, Springer Berlin Heidelberg (2008).
[49]Manual of MacTempas.
[50]JEMS software package that is developed by Pierre Stadelmann, http://cimesg1.epfl.ch/CIOL/ems.html
[51] L. Ouyang, E. S. Thrall, M. M. Deshmukh, H. Park, Adv. Mater. 2006, 18, 1437–1440
[52] D. Shinoda, S. J. Asanabe, J. Phys. Soc. Jpn.1966 21, 555
[1]K. Seo, K. S. K. Varadwaj, P. Mohanty, S. Lee, Y. Jo, M. H. Jung, J. Kim, B. Kim,Nano Lett. 7, 1240 (2007)
[2]P. Hohenberg and W. Kohn, Phys. Rev. 136, B864 _1964_; W.
[3]J. P. Perdew, K. Burke, and M. Ernzerhof, Phys. Rev. Lett. 77 (1996) 3865
[4]D. Shinoda, S. J. Asanabe, J. Phys. Soc. Jpn. 21, 555 (1966)
[5]R. J. Bell, P. Dean, Phil. Mag. 25, 1381 (1972)
[6] C. L. Kuo, S. Lee and G. S. Hwang, J. Appl. Phys. 104, 054906 (2008)
[7] I. Žutić, J. Fabian, S. D Sarma, Rev. Mod. Phys. 76, 323 (2004).
[8] 曾謹言、凡異，量子力學(2001)
[9] J. Osorio-Guillén, S. Lany, S. V. Barabash, and A. Zunger, Phys.Rev. Lett. 96, 107203 _2006_.
[10]D. M. Edwards and M. I. Katsnelson, J. Phys.: Condens. Matter 18, 7209 _2006_.
[11]A. N. Andriotis, R. M. Sheetz, and M. Menon, J. Phys.: Condens.Matter 17, L35 (2005).
[1]K. Seo, K. S. K. Varadwaj, P. Mohanty, S. Lee, Y. Jo, M. H. Jung, J. Kim, B. Kim,Nano Lett. 7, 1240 (2007)
[2]P. Hohenberg and W. Kohn, Phys. Rev. 136, B864 _1964_; W.
[3]J. P. Perdew, K. Burke, and M. Ernzerhof, Phys. Rev. Lett. 77 (1996) 3865
[4]L. F. Mattheiss, Physical Review B 43, 12549 (1991)
[5]D. Shinoda, S. J. Asanabe, J. Phys. Soc. Jpn. 21, 555 (1966)
[6]M. C. Bost and John E. Mahan, J. Appl. Phys. 63, 839 (1988)
[7]R. J. Bell, P. Dean, Phil. Mag. 25, 1381 (1972)
[8] C. L. Kuo, S. Lee and G. S. Hwang, J. Appl. Phys. 104, 054906 (2008)
[9] I. Žutić, J. Fabian, S. D Sarma, Rev. Mod. Phys. 76, 323 (2004).
[10]曾謹言、凡異，量子力學(2001)
[11]A.R Smith, L. Eyring, Ultramicroscopy 8, 65-78 (1982)
[12]J. Kubler, J. Magn. Magn. Mater. 20, 277 (1980)
[13]S. P. Lewis, P. B. Allen, T. Sasaki, Phys. Rev. B, 55, 10253 (1997)
[14]P. S. Robbert, H. Geisler, C. A. Ventrice, J. van Ek, S. Chaturvedi, J. A. Rodriguez, M. Kuhn, U. Diebold, J. Vac. Sci. Technol. A 16, 990 (1998)
[1] L. Ouyang, E. S. Thrall, M. M. Deshmukh, H. Park, Adv. Mater. 2006, 18, 1437–1440
[2]D. Shinoda, S. J. Asanabe, J. Phys. Soc. Jpn. 21, 555 (1966)
[3]P. Hohenberg and W. Kohn, Phys. Rev. 136, B864 _1964_; W.
[4]J. P. Perdew, K. Burke, and M. Ernzerhof, Phys. Rev. Lett. 77 (1996) 3865
[5] T.C. Hou, Y. H. Han, S. C. Lo, C. T. Lee, H. Ouyang, L. J. Chen, Appl. Phys. Lett. 98, 193104 (2011).
[6]K. Seo, K. S. K. Varadwaj, P. Mohanty, S. Lee, Y. Jo, M. H. Jung, J. Kim, B. Kim,Nano Lett. 7, 1240 (2007)
[7]R. J. Bell, P. Dean, Phil. Mag. 25, 1381 (1972)
[8] C. L. Kuo, S. Lee and G. S. Hwang, J. Appl. Phys. 104, 054906 (2008)
[9] I. Žutić, J. Fabian, S. D Sarma, Rev. Mod. Phys. 76, 323 (2004).
[10] 曾謹言、凡異，量子力學(2001)
[1]K. Seo, K. S. K. Varadwaj, P. Mohanty, S. Lee, Y. Jo, M. H. Jung, J. Kim, B. Kim,Nano Lett. 7, 1240 (2007)
[2] L. Ouyang, E. S. Thrall, M. M. Deshmukh, H. Park, Adv. Mater. 2006, 18, 1437–1440