中国物理B ›› 2010, Vol. 19 ›› Issue (1): 17101-017101.doi: 10.1088/1674-1056/19/1/017101

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First-principles study of La and Sb-doping effects onelectronic structure and optical properties of SrTiO3

张志勇1, 闫军锋1, 邓周虎1, 贠江妮2   

  1. (1)School of Information Science and Technology, Northwest University, Xi'an 710127, China; (2)School of Information Science and Technology, Northwest University, Xi'an 710127, China;Institute of Photonics and Photon-Technology of Northwest University, Xi'an 710069, China
  • 收稿日期:2009-05-08 修回日期:2009-07-23 出版日期:2010-01-15 发布日期:2010-01-15
  • 基金资助:
    Project supported by the Northwest University (NWU) Graduate Innovation and Creativity Funds (Grant No. 08YZZ47) and the Natural Science Foundation of Shaanxi Province of China (Grant No. 2009JM8013).

First-principles study of La and Sb-doping effects on electronic structure and optical properties of SrTiO3

Yun Jiang-Ni(贠江妮)a)b), Zhang Zhi-Yong(张志勇)a), Yan Jun-Feng(闫军锋)a), and Deng Zhou-Hu(邓周虎) a)   

  1. a School of Information Science and Technology, Northwest University, Xi'an 710127, China; b Institute of Photonics and Photon-Technology of Northwest University, Xi'an 710069, China
  • Received:2009-05-08 Revised:2009-07-23 Online:2010-01-15 Published:2010-01-15
  • Supported by:
    Project supported by the Northwest University (NWU) Graduate Innovation and Creativity Funds (Grant No. 08YZZ47) and the Natural Science Foundation of Shaanxi Province of China (Grant No. 2009JM8013).

摘要: The effects of La and Sb doping on the electronic structure and optical properties of SrTiO3 are investigated by first-principles calculation of the plane wave ultra-soft pseudo-potential based on density functional theory. The calculated results reveal that corner-shared TiO6 octahedra dominate the main electronic properties of SrTiO3, and its structural stability can be improved by La doping. The La3+ ion fully acts as an electron donor in Sr0.875La0.125TiO3 and the Fermi level shifts into the conduction bands (CBs) after La doping. As for SrSb0.125Ti0.875O3, there is a distortion near the bottom of the CBs for SrSb0.125Ti0.875O3 after Sb doping and an incipient localization of some of the doped electrons trapped in the Ti site, making it impossible to describe the evolution of the density of states (DOS) within the rigid band model. At the same time, the DOSs of the two electron-doped systems shift towards low energies and the optical band gaps are broadened by about 0.4 and 0.6 eV for Sr_0.875La_0.125TiO3 and SrSb0.125Ti0.875O3, respectively. Moreover, the transmittance of SrSb0.125Ti0.875O3 is as high as 95\% in most of the visible region, which is higher than that of Sr0.875La0.125TiO_3 (85\%). The wide band gap, the small transition probability and the weak absorption due to the low partial density of states (PDOS) of impurity in the Fermi level result in the significant optical transparency of SrSb_0.125Ti_0.875O3.

Abstract: The effects of La and Sb doping on the electronic structure and optical properties of SrTiO3 are investigated by first-principles calculation of the plane wave ultra-soft pseudo-potential based on density functional theory. The calculated results reveal that corner-shared TiO6 octahedra dominate the main electronic properties of SrTiO3, and its structural stability can be improved by La doping. The La3+ ion fully acts as an electron donor in Sr0.875La0.125TiO3 and the Fermi level shifts into the conduction bands (CBs) after La doping. As for SrSb0.125Ti0.875O3, there is a distortion near the bottom of the CBs for SrSb0.125Ti0.875O3 after Sb doping and an incipient localization of some of the doped electrons trapped in the Ti site, making it impossible to describe the evolution of the density of states (DOS) within the rigid band model. At the same time, the DOSs of the two electron-doped systems shift towards low energies and the optical band gaps are broadened by about 0.4 and 0.6 eV for Sr0.875La0.125TiO3 and SrSb0.125Ti0.875O3, respectively. Moreover, the transmittance of SrSb0.125Ti0.875O3 is as high as 95% in most of the visible region, which is higher than that of Sr0.875La0.125TiO3 (85%). The wide band gap, the small transition probability and the weak absorption due to the low partial density of states (PDOS) of impurity in the Fermi level result in the significant optical transparency of SrSb0.125Ti0.875O3.

Key words: density functional theory, SrTiO3, doping, electronic structure

中图分类号:  (Other inorganic compounds)

  • 71.20.Ps
61.72.up (Other materials) 71.15.Mb (Density functional theory, local density approximation, gradient and other corrections) 78.20.Ci (Optical constants (including refractive index, complex dielectric constant, absorption, reflection and transmission coefficients, emissivity)) 78.40.Ha (Other nonmetallic inorganics)