p轨道占位库仑排斥对Mg₂Sn电学性质的影响
Effects of p-Orbital On-Site Coulumb Repulsion on the Electronic Properties of Mg₂Sn

DOI: 10.12677/CMP.2014.34006, PP. 39-45

Keywords: GGA + U，占位库仑排斥，电学性质
GGA + U, On-Site Coulumb Repulsion, Electronic Properties

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Abstract:

利用基于密度泛函理论的广义梯度近似方法计算了Mg₂Sn的能带结构、能态密度、差分电荷密度和介电函数。为了考虑Sn中5p轨道的强电子关联效应，我们采用GGA + U的方法计算Mg₂Sn的电学性质。当有效U值为0 eV时，Mg₂Sn带隙为负，与实验值相差较大。当有效U值为1.88eV时，间接带隙为0.30 eV，与实验值吻合较好。差分电荷密度的计算表明Mg₂Sn中Sn-Sn键相对于Sn-Mg键有着较强的共价性，符合实际情况，介电函数的计算结果也与实验结果基本一致。这些证实p轨道占位库仑排斥对Mg₂Sn的电学性质有着较大的影响。
The band structure, density of states, electron density difference and dielectric function of Mg₂Sn are investigated systematically by using the generalized gradient approximation based on density functional theory. To describe the strong electron correlation in the Sn 5p states, the GGA plus on-site repulsion method (GGA+U) is used in the electrical properties calculation of Mg₂Sn. It is found that the band gap is negative with the effective U value of 0 eV, which is quite different from the experimental result. As the effective U value of 1.88 eV is considered, the compound is a semi-conductor with an indirect band gap of 0.30 eV, which agrees with the previous experimental ob-servation satisfactorily. The calculations of electron density difference show that the covalent bond between Sn-Sn is stronger than the covalent bond between Sn-Mg, which is accordant with the practical situation. The calculation of dielectric function agrees well with the experimental result, too. The important influence of the p-orbital on-site Coulumb repulsion for the electronic properties of Mg₂Sn is confirmed.

References

[1]	Bougreios, J., Tobola, J., Wiendlocha, B., Chaput, L., Zwolenski, P., Recour, Q. and Scherrer, H. (2013) Study of elec-tion, phonon and crystal stability versus thermoelectric properties in Mg2X(X = Si, Sn) compounds and their alloys. Functional Materials Letters, 6, 1340005.
[2]	Noda, Y., Kon, H., Furukawa, Y., Otsuka, N., Nishida, I.A. and Ma-sumoto, K. (1992) Temperature dependence of thermoelectric properties of Mg2Si0.6Ge0.4. Materials Transactions. JIM, 33, 851-855.
[3]	Snyder, J.G. and Toberer, E.S. (2008) Complex thermoelectric materials. Nature Materials, 7, 105-114.
[4]	Daniel, K., Bed, P., Hsien-Ping, F., Caylor, J.C., Yu, B., Yan, X., Ma, Y., Wang, X.W., Wang, S.Z., Muto, A., Kenneth, M., Matteo, C., Ren, Z.F. and Chen, G. (2011) High-performance flat-panel solar thermoelectric generators with high thermal concentration. Nature Materials, 10, 532-538.
[5]	Yu, F., Sun, J.X. and Chen, T.H. (2011) High-pressure phase transitions of Mg2Ge and Mg2Sn: First-principles calculations. Physica B, 406, 1789-1794.
[6]	Kutorasinski, K., Wiendlocha, B., Tobola, J. and Kaprzyk, S. (2014) Importance of relativistic effects in electronic structure and thermopower calculations for Mg2Si, Mg2Ge, Mg2Sn. Physical Review B, 89, 115205.
[7]	Stella, A., Brothers, A.D., Hopkins, R.H. and Lynch, D.W. (1967) Pressure coefficient of the band gap in Mg2Si, Mg2Ge, and Mg2Sn. physica Status Solidi, 23, 697-702.
[8]	Premlata, P. and Sankar, P.S. (2011) First prin-ciples study of electronic,elastic and lattice dynamical properties of Mg2X (X = Si, Ge and Sn) compounds. Indian Journal of Pure & Applied Physics, 49, 692-697.
[9]	Buchenauer, C.J. and Cardona, M. (1971) Raman Scattering in Mg2Si, Mg2Ge, and Mg2Sn. Physical Review B, 3, 2504-2507.
[10]	Scouler, W.J. (1969) Optical properties of Mg2Si, Mg2Ge and Mg2Sn from 0.6 to 11.0 eV at 77 degK. Physical Review, 178, 1353-1357.
[11]	Blunt, R.F., Frederikse, H.P.R. and Hosler, W.R. (1955) Electrical and optical properties of intermetallic compounds IV magnesium stannide. Physical Review, 100, 663-666.
[12]	Karazhanov, S.Z., Ravindran, P., Kjekshus, A., Fjellvag, H., Grossner, U. and Svensson, B.G. (2006) Coulomb correlation effects in zinc monochalcogenides. Journal of Applied Physics, 100, Article ID: 043709.
[13]	Droghetti, A., Pemmaraju, C.D. and Sanvito, S. (2008) Predicting d0 magnetism: Self-interaction correction scheme. Physical Review B, 78, Article ID: 140404(R).
[14]	Vladimir, I.A., Jan, Z. and Ole, K.A. (1991) Band theory and Mott insulators: Hubbard U instead of Stoner I. Physical Review B, 44, 943-954.
[15]	Ylvisaker, E.R., Singh, R.R.P. and Picktt, W.E. (2010) Orbital order, stacking defects, and spin fluctuations in the p-electron molecular solid RbO2. Physical Review B, 81, Article ID: 180405(R).
[16]	Coey, J.M.D. (2005) d0 ferromagnetism. Solid State Sciences, 7, 660-667.
[17]	Kovacik, R. and Ederer, C. (2009) Correlation effects in p-electron magnets: Electronic structure of RbO2 from first principles. Physical Review B, 80, Article ID: 140411.
[18]	Mim, K., Kim, B.H., Choi, C.H. and Min, B.I. (2009) Antiferromagnetic and structural transitions in the superoxide KO2 from first principles: A 2p-electron system with spin-orbital-lattice coupling. Physical Review B, 81, Article ID: 100409(R).
[19]	Deng, X.Y., Liu, G.H., Jing, X.P. and Tian, G.S. (2014) On-site correlation of p-electron in d10 semiconductor zinc oxide. International Journal Quantum Chemistry, 114, 468-472.
[20]	Duman, S., Tutuncu, H.M., Bagci, S. and Srivastava, G.P. (2007) Ab initio determination of structural and dynamical properties of Mg2Sn. AIP Conference Proceedings, 899, 247-248.
[21]	Segall, M.D., Lindan, P.L.D., Probert, M.J., Pickard, C., Hasnip, P.J., Clark, S.J. and Payne, M.C. (2002) First-prin- ciples simulation: Ideas, illustrations and the CASTEP code. Journal of Physics-Condensed Matter, 14, 2717- 2744.
[22]	李鹏博, 潘荣凯, 马丽, 王明辉, 卞楠, 唐壁玉, 彭立明, 丁文江 (2014) Mg2Sn的弹性性能和电子结构的第一性原理计算. 广西大学学报(自然科学版), 3, 479-483.
[23]	Wang, J.Y. and Zhou, Y.C. (2004) Polymorphism of Ti3SiC2 ceramic: First-principles investigations. Physical Review B, 69, Article ID: 144108.
[24]	Ravindran, P., Fast, L., Korzhavyi, P.A., Johansson, B., Wills, J. and Eriksson, O. (1998) Density functional theory for calculation of elastic properties of orthorhomcic crystals: Applications to TiSi. Journal of Applied Physics, 84, 4891- 4904.
[25]	沈学础 (2002) 半导体光谱和光学性质. 科学出版社，北京.
[26]	方容川 (2001) 固体光谱学. 中国科学技术大学出版社，合肥.
[27]	Au-Yang, M.Y. (1969) Electronic structure and optical properties of Mg2Si, Mg2Ge, and Mg2Sn. Physical Review, 178, 1358-1364.

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