计算了SrTiO3-δ(δ=0,δ=0.125)体系电子结构,分析了氧空位对SrTiO3晶体的价键结构、能带、态密度、分波态密度、差分电荷密度的影响.所有计算都是基于密度泛函理论(DFT)框架下的第一性原理平面波超软赝势方法.计算结果表明:当氧空位浓度δ=0.125时,空位在母体化合物SrTiO3中引入了大量的传导电子,费米能级进入导带,体系显示金属型导电性.由于空位掺杂,导带底附近的态密度发生了畸变,刚性能带模型不再适合描述SrTiO2.875体系.同时,在导带底附近距离费米能级0.3eV处引入了空位能级,这和实验测得的SrTiO3材料内中性氧空位的电离能约为0.4eV相符.此外,Mulliken布局分析、分波态密度和差分电荷密度分析表明,该空位能级主要由与其最近邻的两个Ti原子的3d电子态贡献,并且由该空位引入的导电电子大部分都局域在空位最近邻的两个Ti原子周围.最后,计算了三种典型平衡条件下SrTiO3晶体内中性氧空位的形成能.
The electronic structure calculations including the Mulliken population analysis,band structure,density of states (DOS),partial density of states (PDOS) and electron density difference on SrTiO3-δwithδ=0 and δ=0.125 were performed by the first-principles calculation of plane wave ultrasoft pseudo-potential technology based on the density function theory (DFT).The calculated results revealed that due to the oxygen(O) vacancy electron doping,the Fermi level moved into conduction bands(CBs) for SrTiO3-δ with δ=0.125 and the system showed metallic behavior.There was a new defect level below the bottommost of CBs when one 0 vacancy was introduced.The 3d states of the two Ti atoms nearest to the vacancy made significant contribution to it.The electrons introduced by the O vacancy were largely localized on the two nearest Ti atoms.Furthermore,the formation energies of neutral O vacancy were calculated in three typical equilibrium conditions.
参考文献
| [1] | Reihl B;Bednorz J G;Moiler K A et al.Electronic structure of strontium titanate[J].Physical Review B,1984,30:803-806. |
| [2] | Shanthi N.;Sarma DD. .Electronic structure of electron doped SrTiO3: SrTiO3-delta and Sr1-xLaxTiO3[J].Physical Review.B.Condensed Matter,1998(4):2153-2158. |
| [3] | R. Astala;P. D. Bristowe .Ab initio and classical simulations of defects in SrTiO_3[J].Computational Materials Science,2001(1/2):81-86. |
| [4] | Gong W;Yun H;Ning Y B et al.Oxygen-deficient SrTiO3-x,x=0.28,0.17,and 0.08 crystal growth,crystal structure,magnetic,and transport properties[J].Journal of Solid State Chemistry,1991,90:320-330. |
| [5] | Akira Uedono;Kazuo Shimayama;Masahiro Kiyohara;Zhi Quan Chen;Kikuo Yamabe .Study of oxygen vacancies in SrTiO_(3) by positron annihilation[J].Journal of Applied Physics,2002(5):2697-2702. |
| [6] | Luo W D;Dun W H;Louie S T et al.Structural and electronic properties of n-doped and P-doped SrTiO3[J].Physical Review B,2004,70:214109-1-214109-8. |
| [7] | 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. |
| [8] | Tetsuya Y;Hiroshi K Y .Physics and control of valencestates in ZnO by codoping method[J].Physica B,2001,302-303:155-163. |
| [9] | Bocquet AE.;Morikawa K.;Fujimori A.;Barman SR.;Maiti K. Sarma DD.;Tokura Y.;Onoda M.;Mizokawa T. .ELECTRONIC STRUCTURE OF EARLY 3D-TRANSITION-METAL OXIDES BY ANALYSIS OF THE 2P CORE-LEVEL PHOTOEMISSION SPECTRA[J].Physical Review.B.Condensed Matter,1996(3):1161-1170. |
| [10] | Cai MQ;Yin Z;Zhang M S .Optical properties of strontium titanate by ab initio calculation within density functional theory[J].Chemical Physics Letters,2004,388:223-227. |
| [11] | Jones R O;Gunnarsson O .The density functional formalism,its applications and prospects[J].Reviews of Modern Physics,1989,61:689-746. |
| [12] | Van Benthem K;Elsassser C;French R H .Bulk electronic structure of SrTiOB3 B:Experiment and theory[J].Journal of Applied Physics,2001,90:6156-6164. |
| [13] | segall M D;Shah R;Pickard C J et al.Population analysis of plane-wave electronic structure calculations of bulk materials[J].Physical Review B,1996,54:16317-16320. |
| [14] | Raevski IP.;Fisenko AV.;Prosandeyev SA.;Osipenko IA. Tarasenko PF.;Maksimov SM. .Study of intrinsic point defects in oxides of the perovskite family: II. Experiment[J].Journal of Physics. Condensed Matter,1998(36):8015-8032. |
| [15] | Davide R;Giuseppe B;Gianfranco P .Electronic structure of a neutral oxygen vacancy in SrTiO3[J].Physical Review B,2003,68:224105-224113. |
| [16] | Tomohito T;Katsuyuki M;Yuichi I et al.First-principles study on structures and energetics of intrinsic vacancies in SrTiO3[J].Physical Review B,2003,68:205213-205220. |
- 下载量()
- 访问量()
- 您的评分：
-
10%
-
20%
-
30%
-
40%
-
50%