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研究生: 王俊凱
Wang, Chun-Kai
論文名稱: CuB2O4晶體在第一原理的研究
Ab initio study of the anti-ferromagnetic, non-collinear CuB2O4 crystal
指導教授: 陳穎叡
Chen, Yiing-Rei
學位類別: 碩士
Master
系所名稱: 物理學系
Department of Physics
論文出版年: 2019
畢業學年度: 107
語文別: 中文
論文頁數: 31
中文關鍵詞: 第一原理晶體結構能帶分析
英文關鍵詞: first-pronciple, CuB2O4, non-collinear calculation
DOI URL: http://doi.org/10.6345/THE.NTNU.DP.001.2019.B04
論文種類: 學術論文
相關次數: 點閱:195下載:24
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  • 研究CuB2O4反鐵磁性材料在第一原理中的能帶架構以及材料特性。
    CuB2O4在第一原理中,使用六個單元的方式呈現週期性的結構分布,在這個晶格中a=11.357、c=5.542 Å, k-mesh使用4x4x4, nbands為400 並且使用VASP GGA+U的方法,其中Cu(A)&Cu(B)的U分別為U1=6.4eV, U2=7.0eV。
    在計算中,我們發現CuB2O4的density of state(DOS)在導帶的地方會出現兩個非常明顯的尖點。一個是由Cu(A)&O(1)組成,另外一個則是由Cu(B)&O(2)&O(3)&O(4)所貢獻,因此我們希望可以分析出兩者的不同。

    Ab initio study of anti-ferromagnetic non-collinear CuB2O4 crystal ,CuB2O4 crystallizes in first-principles calculations, with six formula units were performed using periodic density function theory. The cell of dimensions a=11.357 and c=5.542 Å, k-mesh=4x4x4, nbands=400 and use GGA+U on VASP where U1=6.4eV, U2=7.0eV for Cu(A)&Cu(B).In the case, we found that CuB2O4’s density of state(DOS) has two peaks in conduction band. One is contributed by Cu(A) & O(1), the other one is contributed by Cu(B) & O(2) & O(3) & O(4). As the result of, we can sort atoms to two types. A type is Cu(A) and O(1) which donate states to peak(1), the other type is Cu(B) and O(2)&O(3)&O(4) which donate states to peak(2). And we could do analyze their difference.

    Chapter1 緒論 1 Chapte2 密度泛函理論(DFT)和計算方法 2 2.1 密度泛函理論(Density function theory) 2 2.1.1 The Hohenberg-Kohn theorems 2 2.1.2 The Kohn-Sham equations 4 2.1.3 Exchange-correlation energy 6 2.2 GGA+U method 7 Chapter3 CuB2O4的文獻探討 8 3.1 CuB2O4在基態時的鐵磁性研究(Ferromagnetism in CuB2O4) 8 3.2 CuB2O4在VASP中的鐵磁性計算研究 11 Chapter4 CuB2O4在VASP中的材料計算研究及討論 15 4.1 CuB2O4在VASP中的自洽(self-consistent field method, SCF)材料計算 15 4.2 CuB2O4在VASP中使用GGA+U方法的計算 16 4.2.1 在VASP測試U值的大小 16 4.2.2 CuB2O4在VASP中的收斂(relaxation)計算 19 4.3 CuB2O4材料在導帶上的特徵分析 24 Chapter5 結果與討論 29 參考文獻 31

    1.Andreas Go¨rling. Density-functional theory beyond the Hohenberg-Kohn theorem. Phys. Rev. A 59,3359 (1999)
    2.A.I.Liechtenstein, V.I.Anisimov, and J.Zaanen. Density-functional theory and strong interactions: Orbital ordering in Mott-Hubbard insulators. Phys. Rev. B 52, R5467(R)(1995)
    3.C.F. von WEIZSÄCKER. Z. Phys. 96, 431 (1935)
    4.John P. Perdew and Mel Levy. Physical Content of the Exact Kohn-Sham Orbital Energies: Band Gaps and Derivative Discontinuities. Phys. Rev. Lett. 51, 1884(1983)
    5.Larry Spruch. Pedagogic notes on Thomas-Fermi theory (and on some improvements): atoms, stars, and the stability of bulk matter. Rev. Mod. Phys. 63, 151 (1991)
    6.M. Boehm, B. Roessli, J. Schefer, A. S. Wills, B. Ouladdiaf, E. Lelièvre-Berna, U. Staub, and G. A. Petrakovskii. Complex magnetic ground state of CuB2O4. Phys. Rev. B 68, 024405(2003)
    7.P.A.M. Dirac. Note on Exchange Phenomena in Thomas Atom. Proceedings of the Cambridge Philosophical Society, vol. 26, issue 03, p. 376 (1930)
    8.R. V. Pisarev, I. Sänger, G. A. Petrakovskii, and M. Fiebig. Magnetic-Field Induced Second Harmonic Generation in CuB2O4. Phys. Rev. Lett. 93, 037204(2004)
    9.Vladimir I. Anisimov, Jan Zaanen, and Ole K. Andersen. Band theory and Mott insulators: Hubbard U instead of Stoner. Phys. Rev. B 44, 943(1991)
    10.V.I.Anisimov ,F.Aryasetiawan, and A.I.Liechtenstein. First-principles calculations of the electronic structure and spectra of strongly correlated systems: the LDA+ U method. J.Phys:Condens.Matter, Volume 9, Issue 4, pp. 767-808 (1997)

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