利用第一性原理研究了Ba_8Si_(46)和Ba_8Ag_6Si_(40)笼状化合物的电子性质.对于Ba_8Si_(46),化合物中Ba原子5d轨道与Si原子3s,特别是3p轨道杂化,一方面导致了Ba_8Si_(46)在费米能级附近有很高的态密度,另一方面说明了笼内Ba原子和笼上Si原子之间存在耦合.对于Ba_8Ag_6Si_(40)分析结果表明,由于Ag的5s轨道向Si的3p轨道转移电子,导致Ag与Si原子间成键趋向离子键.带结构显示这两种化合物具有弱金属特征,但Ba_8Ag_6Si_(40)化合物与费米能级相交的带宽较大,预期这种化合物具有更好的导电性能.
The population and density of states of electrons of Ba_8Si_(46) and Ba_8Ag_6Si_(40) were analyzed in the paper. The Ba_8Si_(46) results show Ba 6s electrons are transferred into the Ba 5d and Si 3p orbits. The sp3 hybridizations of framework Si make the compound posses stabile structure. For Ba_8Ag_6Si_(40), Ag 5s electrons are transferred into the Si 3p orbits.The Ag doping destroys sp3 hybridizations of framework Si. The bond between Ag and Si atoms tends to electrovalent bond. The band structures of Ba_8Si_(46) and Ba_8Ag_6Si_(40) indicate that they are weak metal. Because the band width intersecting with Eermi level for Ba_8Ag_6Si_(40) is larger than Ba_8Si_(46), Ba_8Ag_6Si_(40) compound has higher conductance than Ba_8Si_(46).
参考文献
| [1] | Okamoto N L;Oh M W;Nishii T et al.Crystal Structure and Thermoelectric Properties of the Type-clathrate Compound Ba8Ge43 with an Ordered Arrangement of Ge Vacancies[J].Journal of Applied Physics,2006,99(1-8):033513. |
| [2] | Kim J H;Okamoto N L;Kishida K et al.Crystal Structure and Thermoelectric Properties of Type-III Cathrate Compounds in the Ba-In-Ge System[J].Journal of Applied Physics,2007,102(1-9):094506. |
| [3] | Kim JH;Okamoto NL;Kishida K;Tanaka K;Inui H .Thermoelectric properties and crystal structure of type-III clathrate compounds in the Ba-Al-Ge system[J].Journal of Applied Physics,2007(3):034510-1-034510-9-0. |
| [4] | Miyoshi T;Imai M;Ohmura R;Yasuoka K .Thermodynamic stability of type-I and type-II clathrate hydrates depending on the chemical species of the guest substances[J].The Journal of Chemical Physics,2007(23):34506-1-34506-6-0. |
| [5] | Gou WP;Li Y;Chi J;Ross JH;Beekman M;Nolas GS .NMR study of slow atomic motion in Sr8Ga16Ge30 clathrate[J].Physical review, B. Condensed matter and materials physics,2005(17):4307-1-4307-6-0. |
| [6] | Pacheco V;Bentien A;Carrillo-Cabrera W;Paschen S;Steglich F;Grin Y .Relationship between composition and charge carrier concentration in Eu8Ga16-xGe30+x clathrates[J].Physical review, B. Condensed matter and materials physics,2005(16):5205-1-5205-10-0. |
| [7] | Suekuni K;Avila MA;Umeo K;Takabatake T .Cage-size control of guest vibration and thermal conductivity in Sr8Ga16Si30-xGex[J].Physical review, B. Condensed matter and materials physics,2007(19):5210-1-5210-6-0. |
| [8] | Miranda CR;Antonelli A .Thermodynamics of type-I and type-II Si clathrates at zero pressure: Monte Carlo simulations[J].Physical review, B. Condensed matter and materials physics,2006(15):3203-1-3203-4-0. |
| [9] | Fang SL.;Eklund PC.;Dresselhaus G.;Dresselhaus MS. Kawaji H.;Yamanaka S.;Grigorian L. .Raman scattering from vibrational modes in Si-46 clathrates[J].Physical Review.B.Condensed Matter,1998(13):7686-7693. |
| [10] | Reny E.;San-Miguel A.;Guyot Y.;Masenelli B.;Melinon P.;Saviot L. Yamanaka S.;Champagnon B.;Cros C.;Pouchard M.;Borowski M.;Dianoux AJ. .Vibrational modes in silicon clathrate compounds: A key to understanding superconductivity - art. no. 014532[J].Physical Review.B.Condensed Matter,2002(1):4532-0. |
| [11] | Yokoya T.;Kiss T.;Kobayashi K.;Shin S.;Moriguchi K. Shintani A.;Fukuoka H.;Yamanaka S.;Fukushima A. .Electronic structure and superconducting gap of silicon clathrate Ba8Si46 studied with ultrahigh-resolution photoemission spectroscopy - art. no. 172504[J].Physical Review.B.Condensed Matter,2001(17):2504-0. |
| [12] | Itou M;Sakurai Y;Usuda M;Cros C;Fukuoka H;Yamanaka S .Compton scattering study of the silicon clathrate Ba8Si46: Experiment and theory[J].Physical review, B. Condensed matter and materials physics,2005(12):5125-1-5125-4-0. |
| [13] | Connetable D.;Timoshevskii V.;Masenelli B.;Beille J.;Marcus J. Barbara B.;Saitta AM.;Rignanese GM.;Melinon P.;Yamanaka S.;Blase X. .Superconductivity in doped sp(3) semiconductors: The case of the clathrates - art. no. 247001[J].Physical review letters,2003(24):7001-0. |
| [14] | Johnsen S;Bentien A;Madsen GKH;Iversen BB;Nygren M .Crystal structure, band structure, and physical properties of Ba8Cu6-xGe40+x (0 <= x <= 0.7)[J].Chemistry of Materials: A Publication of the American Chemistry Society,2006(19):4633-4642. |
| [15] | Qiu L;Swainson I P;Nolas G S et al.Structure,Thermal and Transport Properties of the Clathrates Sr_8Zn_8Ge_(38),Sr_8Ga_(16)Ge_(30),and Ba8Ga16Si30[J].Physical Review B:Condensed Matter,2004,70(1-8):035208. |
| [16] | Kamakura N;Nakano T;Ikemoto Y;Usuda M;Fukuoka H;Yamanaka S;Shin S;Kobayashi K .Role of Ag doping in Ba8Si46 compounds[J].Physical review, B. Condensed matter and materials physics,2005(1):4511-1-4511-6-0. |
| [17] | Fujita I;Kishimoto K;Sato M;Anno H;Koyanagi T .Thermoelectric properties of sintered clathrate compounds Sr8GaxGe46-x with various carrier concentrations[J].Journal of Applied Physics,2006(9):93707-1-93707-8-0. |
| [18] | Myles CW;Biswas K;Nenghabi E .Rattling "guest" impurities in SI and Ge clathrate semiconductors[J].Physica, B. Condensed Matter,2007(0):695-698. |
| [19] | Melnychenko-Koblyuk N;Grytsiv A;Rogl P;Rotter M;Bauer E;Durand G;Kaldarar H;Lackner R;Michor H;Royanian E .Clathrate formation in the Ba-Pd-Ge system: Phase equilibria, crystal structure, and physical properties[J].Physical review, B. Condensed matter and materials physics,2007(14):144118-1-144118-11-0. |
| [20] | 熊聪,邓书康,唐新峰,祁琼,张清杰.Zn掺杂n型笼合物Ba8Ga16-2xZnxGe30+x的热电传输特性[J].物理学报,2008(02):1190-1196. |
| [21] | Segall MD.;Lindan PJD.;Probert MJ.;Pickard CJ.;Hasnip PJ.;Clark SJ. Payne MC. .First-principles simulation: ideas, illustrations and the CASTEP code[J].Journal of Physics. Condensed Matter,2002(11):2717-2744. |
| [22] | Ouyang CY;Xiong ZH;Ouyang QZ;Liu GD;Ye ZQ;Lei MS .First principles study on the structural, electronic and optical properties of diluted magnetic semiconductors Zn1-xCoxX (X=S, Se, Te)[J].Chinese physics,2006(7):1585-1590. |
| [23] | 段满益,徐明,周海平,沈益斌,陈青云,丁迎春,祝文军.过渡金属与氮共掺杂ZnO电子结构和光学性质的第一性原理研究[J].物理学报,2007(09):5359-5365. |
| [24] | Payne M C;Teper M P;Allan D C et al.Joannopoulos,Iterative Minimization Techniques for Ab Initiototal-energy Calculations:Molecular Dynamics and Conjugate Gradients[J].Reviews of Modern Physics,1992,64:1045-1097. |
| [25] | Perdew J P;Burke K;Ernzerhof M .Generalized Gradient Approximation Made Simple[J].Physical Review Letters,1996,77:3865-3868. |
| [26] | 季正华,曾祥华,胡永金,谭明秋.高压下ZnSe的电子结构和光学性质[J].物理学报,2008(06):3753-3759. |
| [27] | Vanderbilt D .Soft Self-consistent Pseudopotentials in a Generalized Eigenvalue Formalism[J].Physical Review B,41:7892-7895. |
| [28] | Tse JS.;Desgreniers S.;Li ZQ.;Ferguson MR.;Kawazoe Y. .Structural stability and phase transitions in K8Si46 clathrate under high pressure - art. no. 195507[J].Physical review letters,2002(19):5507-0. |
| [29] | Herrmann RFW.;Kuroshima S.;Suematsu H.;Tanigaki K. .Superconductivity in silicon based barium-inclusion clathrates[J].Chemical Physics Letters,1998(1/2):29-32. |
| [30] | 丁迎春,向安平,徐明,祝文军.掺稀土元素（Y,La）的γ-Si3N4的电子结构和光学性质[J].物理学报,2007(10):5996-6002. |
| [31] | Tse J S;Iitaka T;Kume T et al.Electronic Structure and Vibrational Properties of Ba_8Si_(46),Ba8AgnSi46-n,and Ba8AunSi46-n[J].Physical Review B:Condensed Matter,2005,72(1-9):155441. |
| [32] | 熊志华,王建敏,雷敏生.用第一性原理研究金属铜的电子结构[J].江西科学,2005(03):217-220. |
| [33] | Gryko J.;Sankey OF.;Mcmillan PF. .NMR STUDIES OF NA ATOMS IN SILICON CLATHRATE COMPOUNDS[J].Physical Review.B.Condensed Matter,1996(5):3037-3039. |
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