• DOI:10.1038/ncomms11602
• Corpus ID: 17212212

Domain topology and domain switching kinetics in a hybrid improper ferroelectric

@article{Huang2016DomainTA,
  title={Domain topology and domain switching kinetics in a hybrid improper ferroelectric},
  author={Fei-Ting Huang and Fei Xue and Bin Gao and L. H. Wang and X. Luo and Wei Cai and X. Z. Lu and James M. Rondinelli and L. Q. Chen and S. -W. Cheong},
  journal={Nature Communications},
  year={2016},
  volume={7}
}

• F. Huang, F. Xue, +7 authors S. Cheong
• Published 29 February 2016
• Physics
• Nature Communications

Charged polar interfaces such as charged ferroelectric walls or heterostructured interfaces of ZnO/(Zn,Mg)O and LaAlO3/SrTiO3, across which the normal component of electric polarization changes suddenly, can host large two-dimensional conduction. Charged ferroelectric walls, which are energetically unfavourable in general, were found to be mysteriously abundant in hybrid improper ferroelectric (Ca,Sr)3Ti2O7 crystals. From the exploration of antiphase boundaries in bilayer-perovskites, here we discover that each of four polarization-direction states is degenerate with two antiphase domains, and these eight structural variants form a Z4 × Z2 domain structure with Z3 vortices and five distinct types of domain walls, whose topology is directly relevant to the presence of abundant charged walls. We also discover a zipper-like nature of antiphase boundaries, which are the reversible creation/annihilation centres of pairs of two types of ferroelectric walls (and also Z3-vortex pairs) in 90° and 180° polarization switching. Our results demonstrate the unexpectedly rich nature of hybrid improper ferroelectricity. Charged ferroelectric domain walls show promise for two-dimensional conduction, but their abundance within (Ca,Sr)3Ti2O7 crystals is poorly understood. Here, Huang et al. discover topology related domain structures in such materials, which reveal the rich nature of hybrid improper ferroelectricity.