中国物理B ›› 2011, Vol. 20 ›› Issue (10): 106102-106102.doi: 10.1088/1674-1056/20/10/106102
倪利红1, 任召辉1, 宋晨路1, 韩高荣1, 刘涌2
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)
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.
中图分类号: (Crystallographic aspects of phase transformations; pressure effects)