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Ga2基Heusler合金Ga2XCr(X = Mn, Fe, Co, Ni, Cu)的四方畸变、电子结构、磁性及声子谱的第一性原理计算

陈家华 刘恩克 李勇 祁欣 刘国栋 罗鸿志 王文洪 吴光恒

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Ga2基Heusler合金Ga2XCr(X = Mn, Fe, Co, Ni, Cu)的四方畸变、电子结构、磁性及声子谱的第一性原理计算

陈家华, 刘恩克, 李勇, 祁欣, 刘国栋, 罗鸿志, 王文洪, 吴光恒

First-principles investigations on tetragonal distortion, electronic structure, magnetism, and phonon dispersion of Ga2XCr (X = Mn, Fe, Co, Ni, Cu) Heusler alloys

Chen Jia-Hua, Liu En-Ke, Li Yong, Qi Xin, Liu Guo-Dong, Luo Hong-Zhi, Wang Wen-Hong, Wu Guang-Heng
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  • 运用基于密度泛函理论的第一性原理的方法, 对Ga2基Heusler合金Ga2XCr (X = Mn, Fe, Co, Ni, Cu)的四方畸变、电子结构、磁性及声子谱特性进行了系统的研究. 结果表明, 在保持体积不变的四方畸变中, 五种合金的磁矩主要由Cr元素提供; Ga2FeCr, Ga2CoCr和Ga2CuCr保持稳定的立方相, 而在Ga2MnCr和Ga2NiCr 中观察到能量更低的四方相, 且其能量最低点对应的c/a分别位于1.28和1.11处, 而对应的能量差ΔE 分别为-8.26 meV和-6.14 meV. 电子结构显示, Ga2MnCr和Ga2 NiCr的费米能级附近存在尖锐的电子态密度峰, 导致3d电子能级杂化向宽能量范围扩展, 以消除体系的高能量不稳态, 这个过程导致结构转变的发生. 基于适度的畸变度和能量差, 本文认为Ga2MnCr有存在铁磁马氏体相变的可能, 其声学支虚频的出现, 也进一步表明体系有声子模软化的行为.
    In Ga2-based Heusler alloys Ga2XCr (X = Mn, Fe, Co, Ni, Cu) the tetragonal distortion, electronic structure, magnetism and phonon dispersion have been studied by first-principles calculations based on the density functional theory. The volume-conserving tetragonal distortions of the cubic Ga2XCr show that Cr atom makes the greatest contribution to the total magnetic moment. No martensitic transformation has been found in Ga2FeCr, Ga2CoCr and Ga2CuCr. For both Ga2MnCr and Ga2NiCr, the tetragonal phase is lower in energy as compared with the cubic phase. Ga2MnCr and Ga2NiCr have the lowest total energy at c/a = 1.28 and 1.11, respectively. Correspondingly, the energy difference ΔE between the cubic and the tetragonal phase is -8.26 meV in Ga2MnCr and -6.14 meV in Ga2NiCr. For Ga2MnCr and Ga2NiCr, calculations of electronic structure and phonon dispersion reveal that a sharp peak near the Fermi level will lead to a structural instability by increasing the energy of the system, which can result in a broadening in the energy range due to hybridizations between 3d electrons as well as the potential structural transformation. With proper c/a and ΔE a potential tetragonal martensitic transformation can be expected in Ga2MnCr, the phonon dispersion of which further shows that the acoustic modes tend to be softened.
    • 基金项目: 国家自然科学基金(批准号: 51301195, 51275029)资助的课题.
    • Funds: Project supported by the National Natural Science Foundation of China (Grant Nos. 51301195, 51275029).
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    Wu G H, Yu C H, Meng L Q, Chen J L, Yang F M, Qi S R, Zhan W S, Wang Z, Zheng Y F, Zhao L C 1999 Appl. Phys. Lett. 75 2990

    [2]

    Kainuma R, Imano Y, Ito W, Sutou Y, Morito H, Okamoto S, Kitakami O, Oikawa K, Fujita A, Kanomata T, Ishida K 2006 Nature 439 957

    [3]

    Hu F X, Shen B G, Sun J R, Wu G H 2001 Phys. Rev. B 64 132412

    [4]

    Yu S Y, Liu Z H, Liu G D, Chen J L, Cao Z X, Wu G H, Zhang B, Zhang X X 2006 Appl. Phys. Lett. 89 162503

    [5]

    Dubenko I, Pathak A K, Stadler S, Ali N, Kovarskii Y, Prudnikov V N, Perov N S, Granovsky A B 2009 Phys. Rev. B 80 092408

    [6]

    Ma L, Wang W H, Lu J B, Li J Q, Zhen C M, Hou D L, Wu G H 2011 Appl. Phys. Lett. 99 182507

    [7]

    Karaca H E, Karaman I, Basaran B, Ren Y, Chumlyakov Y I, Maier H J 2009 Adv. Funct. Mater. 19 983

    [8]

    Chmielus M, Zhang X X, Witherspoon C, Dunand D C, Mullner P 2009 Nat. Mater. 8 863

    [9]

    Sarawate N, Dapino M 2006 Appl. Phys. Lett. 88 121923

    [10]

    Manosa L, Gonzalez-Alonso D, Planes A, Bonnot E, Barrio M, Tamarit J L, Aksoy S, Acet M 2010 Nat. Mater. 9 478

    [11]

    Webster P J, Ziebeck K R A, Town S L, Peak M S 1984 Philos. Mag. B 49 295

    [12]

    Sutou Y, Imano Y, Koeda N, Omori T, Kainuma R, Ishida K, Oikawa K 2004 Appl. Phys. Lett. 85 4358

    [13]

    Liu Z H, Zhang M, Cui Y T, Zhou Y Q, Wang W H, Wu G H, Zhang X X, Xiao G 2003 Appl. Phys. Lett. 82 424

    [14]

    Liu G, Chen J, Liu Z, Dai X, Wu G, Zhang B, Zhang X 2005 Appl. Phys. Lett. 87 262504

    [15]

    Oikawa K, Ota T, Gejima F, Ohmori T, Kainuma R, Ishida K 2001 Mater. Trans. 42 2472

    [16]

    Wuttig M, Li J, Craciunescu C 2001 Scr. Mater. 44 2393

    [17]

    Xu X, Omori T, Nagasako M, Okubo A, Umetsu R Y, Kanomata T, Ishida K, Kainuma R 2013 Appl. Phys. Lett. 103 164104

    [18]

    Jenkins C, Scholl A, Kainuma R, Elmers H J, Omori T 2012 Appl. Phys. Lett. 100 032401

    [19]

    Zhu W, Liu E K, Feng L, Tang X D, Chen J L, Wu G H, Liu Z H, Meng F B, Luo H Z 2009 Appl. Phys. Lett. 95 222512

    [20]

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    [21]

    Shiraishi H, Hori T, Yamaguchi Y 1992 J. Magn. Magn. Mater. 104-107, Part 3 2040

    [22]

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    [23]

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    Zayak A, Entel P, Rabe K, Adeagbo W, Acet M 2005 Phys. Rev. B 72 054113

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    [29]

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    [30]

    Luo H Z, Jia P Z, Liu G D, Meng F B, Liu H Y, Liu E K, Wang W H, Wu G H 2013 Solid State Commun. 170 44

    [31]

    Luo H Z, Meng F B, Liu G D, Liu H Y, Jia P Z, Liu E K, Wang W H, Wu G H 2013 Intermetallics 38 139

    [32]

    Li G J, Liu E K, Zhang Y J, Du Y, Zhang H W, Wang W H, Wu G H 2013 J. Appl. Phys. 113 103903

    [33]

    Winterlik J, Chadov S, Gupta A, Alijani V, Gasi T, Filsinger K, Balke B, Fecher G H, Jenkins C A, Casper F, Kubler J, Liu G D, Gao L, Parkin S S, Felser C 2012 Adv. Mater. 24 6283

    [34]

    Sahariah M B, Ghosh S, Singh C S, Gowtham S, Pandey R 2013 J. Phys.: Condes. Matter 25 025502

    [35]

    Felser C, Alijani V, Winterlik J, Chadov S, Nayak A K 2013 IEEE Trans. Magn. 49 682

    [36]

    Sozinov A, Likhachev A A, Lanska N, Ullakko K 2002 Appl. Phys. Lett. 80 1746

    [37]

    Lin W, Xu J H, Freeman A J 1992 Phys. Rev. B 45 10863

    [38]

    S. I. Shinpei Fujii, Setsuro Asano 1989 J. Phys. Soc. Jpn. 58 3657

    [39]

    Opeil C P, Mihaila B, Schulze R K, Mañosa L, Planes A, Hults W L, Fisher R A, Riseborough P S, Littlewood P B, Smith J L, Lashley J C 2008 Phys. Rev. Lett. 100 165703

    [40]

    Ye M, Kimura A, Miura Y, Shirai M, Cui Y T, Shimada K, Namatame H, Taniguchi M, Ueda S, Kobayashi K, Kainuma R, Shishido T, Fukushima K, Kanomata T 2010 Phys. Rev. Lett. 104 176401

    [41]

    Stuhr U, Vorderwisch P, Kokorin V V 2000 J. Phys.: Condes. Matter 12 7541

    [42]

    Zayak A T, Adeagbo W A, Entel P, Rabe K M 2006 Appl. Phys. Lett. 88 111903

    [43]

    Zayak A T, Entel P, Rabe K M, Adeagbo W A, Acet M 2005 Phys. Rev. B 72 054113

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出版历程
  • 收稿日期:  2014-05-03
  • 修回日期:  2014-11-03
  • 刊出日期:  2015-04-05

Ga2基Heusler合金Ga2XCr(X = Mn, Fe, Co, Ni, Cu)的四方畸变、电子结构、磁性及声子谱的第一性原理计算

  • 1. 北京化工大学理学院, 北京 100029;
  • 2. 中国科学院物理研究所磁学国家重点实验室, 北京 100190;
  • 3. 河北工业大学材料学院, 天津 300130
    基金项目: 国家自然科学基金(批准号: 51301195, 51275029)资助的课题.

摘要: 运用基于密度泛函理论的第一性原理的方法, 对Ga2基Heusler合金Ga2XCr (X = Mn, Fe, Co, Ni, Cu)的四方畸变、电子结构、磁性及声子谱特性进行了系统的研究. 结果表明, 在保持体积不变的四方畸变中, 五种合金的磁矩主要由Cr元素提供; Ga2FeCr, Ga2CoCr和Ga2CuCr保持稳定的立方相, 而在Ga2MnCr和Ga2NiCr 中观察到能量更低的四方相, 且其能量最低点对应的c/a分别位于1.28和1.11处, 而对应的能量差ΔE 分别为-8.26 meV和-6.14 meV. 电子结构显示, Ga2MnCr和Ga2 NiCr的费米能级附近存在尖锐的电子态密度峰, 导致3d电子能级杂化向宽能量范围扩展, 以消除体系的高能量不稳态, 这个过程导致结构转变的发生. 基于适度的畸变度和能量差, 本文认为Ga2MnCr有存在铁磁马氏体相变的可能, 其声学支虚频的出现, 也进一步表明体系有声子模软化的行为.

English Abstract

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