中国物理B ›› 2011, Vol. 20 ›› Issue (10): 106102-106102.doi: 10.1088/1674-1056/20/10/106102

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Strain-induced ferroelectric phase transitions in incipient ferroelectric rutile TiO2

倪利红1, 任召辉1, 宋晨路1, 韩高荣1, 刘涌2   

  1. (1)Department of Materials Science and Engineering, Zhejiang University, Hangzhou 310027, China; (2)Department of Materials Science and Engineering, Zhejiang University, Hangzhou 310027, China; Angstrom Centre, Institute of Science and Technology, Zhejiang University, Hangzhou 310027, China
  • 收稿日期:2010-06-18 修回日期:2011-06-10 出版日期:2011-10-15 发布日期:2011-10-15
  • 基金资助:
    Project supported by the Scientific Research Foundation of the Education Department of Zhejiang Province, China (Grant No. Y200805750).

Strain-induced ferroelectric phase transitions in incipient ferroelectric rutile TiO2

Ni Li-Hong(倪利红)a), Liu Yong(刘涌) a)b)†, Ren Zhao-Hui(任召辉)a), Song Chen-Lu(宋晨路)a), and Han Gao-Rong(韩高荣) a)   

  1. a Department of Materials Science and Engineering, Zhejiang University, Hangzhou 310027, China; b Angstrom Centre, Institute of Science and Technology, Zhejiang University, Hangzhou 310027, China
  • Received:2010-06-18 Revised:2011-06-10 Online:2011-10-15 Published:2011-10-15
  • Supported by:
    Project supported by the Scientific Research Foundation of the Education Department of Zhejiang Province, China (Grant No. Y200805750).

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摘要： Uniaxial strain induced ferroelectric phase transitions in rutile TiO2 are investigated by first-principles calculations. The calculated results show that the in-plane tensile strain induces rutile TiO2, paraelectric phase with P4-2/mnm (D4h) space group, to a ferroelectric phase with Pm (Cs) space group，driven by the softening behaviour of the E_u1 mode. In addition, the out-of-plane tensile strain, vertical to the ab plane, leads to a ferroelectric phase with P42nm (C4v) space group, driven by the softening behaviour of the A2u mode. The critical tensile strains are 3.7% in-plane and 4.0% out-of-plane, respectively. In addition, the in-plane compression strain, which has the same structure variation as out-of-plane tensile strain due to Poisson effect, leads the paraelectric rutile TiO2 to a paraelectric phase with Pnnm (D2h) space group driven by the softening behaviour of the B1g mode. These results indicate that the sequence ferroelectric (or paraelectric) phase depends on the strain applied. The origin of ferroelectric stabilization in rutile TiO2 is also discussed briefly in terms of strain induced Born effective charge transfer.

关键词: TiO2, epitaxial strain, ferroelectric phase transition, first-principles calculations

Abstract: Uniaxial strain induced ferroelectric phase transitions in rutile TiO2 are investigated by first-principles calculations. The calculated results show that the in-plane tensile strain induces rutile TiO2, paraelectric phase with P4-2/mnm (D4h) space group, to a ferroelectric phase with Pm (Cs) space group，driven by the softening behaviour of the E_u1 mode. In addition, the out-of-plane tensile strain, vertical to the ab plane, leads to a ferroelectric phase with P42nm (C4v) space group, driven by the softening behaviour of the A2u mode. The critical tensile strains are 3.7% in-plane and 4.0% out-of-plane, respectively. In addition, the in-plane compression strain, which has the same structure variation as out-of-plane tensile strain due to Poisson effect, leads the paraelectric rutile TiO2 to a paraelectric phase with Pnnm (D2h) space group driven by the softening behaviour of the B1g mode. These results indicate that the sequence ferroelectric (or paraelectric) phase depends on the strain applied. The origin of ferroelectric stabilization in rutile TiO2 is also discussed briefly in terms of strain induced Born effective charge transfer.

Key words: TiO2, epitaxial strain, ferroelectric phase transition, first-principles calculations

中图分类号:  (Crystallographic aspects of phase transformations; pressure effects)

  • 61.50.Ks
63.20.dk (First-principles theory) 77.80.-e (Ferroelectricity and antiferroelectricity)