Molecular Dynamics Simulation of 90 degrees Ferroelectric Domains in PbTiO3

作者：Nishimatsu Takeshi^*; Aoyagi Kenta; Kiguchi Takanori; Konno Toyohiko J; Kawazoe Yoshiyuki; Funakubo Hiroshi; Kumar Anil; Waghmare Umesh V

来源：Journal of the Physical Society of Japan, 2012, 81(12): 124702.

DOI：10.1143/JPSJ.81.124702

• ferroelectrics
• first-principles effective Hamiltonian
• phase transition
• FFT
• BFTEM

Using molecular dynamics (MD) simulations based on first-principles effective Hamiltonian of bulk PbTiO3, we corroborate the occurrence of 90 degrees ferroelectric domain structures showing that they arise as metastable states only in cooling simulations (as the temperature is lowered) and establish characteristic stability of 90 degrees domain structure in PbTiO3. In contrast, such domains do not manifest in similar simulations of bulk BaTiO3. Through a detailed analysis and comparison between PbTiO3 and BaTiO3, we find that the 90 degrees domain structures are energetically favorable only in the former, and the origin of their stability lies in the polarization-strain coupling. Our analysis suggests that a possible origin of observed 90 degrees domain structure in BaTiO3 has to be extrinsic, such as special boundary condition and/or defect-related inhomogeneities. We present transmission electron microscopy (TEM) images of 90 degrees domain structure in PbTiO3, and compare the observed thickness of domain wall and size of domains with predictions of our simulations.

• 出版日期2012-12