TY - JOUR
T1 - Configurable topological textures in strain graded ferroelectric nanoplates
JF - Nature Communications
Y1 - 2018/
A1 - K.-E. Kim
A1 - S. Jeong
A1 - K. Chu
A1 - J.H. Lee
A1 - G.-Y. Kim
A1 - F. Xue
A1 - T.Y. Koo
A1 - L.-Q. Chen
A1 - S.-Y. Choi
A1 - Ramamoorthy Ramesh
A1 - C.-H. Yang
KW - Article
KW - bismuth
KW - chirality
KW - destruction
KW - discrete element method
KW - electrical property
KW - ferrite
KW - leisure
KW - memory
KW - microscopy
KW - piezoelectricity
KW - vorticity
AB - Topological defects in matter behave collectively to form highly non-trivial structures called topological textures that are characterised by conserved quantities such as the winding number. Here we show that an epitaxial ferroelectric square nanoplate of bismuth ferrite subjected to a large strain gradient (as much as 105 m-1) associated with misfit strain relaxation enables five discrete levels for the ferroelectric topological invariant of the entire system because of its peculiar radial quadrant domain texture and its inherent domain wall chirality. The total winding number of the topological texture can be configured from - 1 to 3 by selective non-local electric switching of the quadrant domains. By using angle-resolved piezoresponse force microscopy in conjunction with local winding number analysis, we directly identify the existence of vortices and anti-vortices, observe pair creation and annihilation and manipulate the net number of vortices. Our findings offer a useful concept for multi-level topological defect memory. © 2018 The Author(s).
PB - Nature Publishing Group
VL - 9
N1 - cited By 23
ER -
TY - JOUR
T1 - Stability of Polar Vortex Lattice in Ferroelectric Superlattices
JF - Nano Letters
Y1 - 2017/
SP - 2246
EP - 2252
A1 - Z. Hong
A1 - A.R. Damodaran
A1 - F. Xue
A1 - S.-L. Hsu
A1 - J. Britson
A1 - A.K. Yadav
A1 - C.T. Nelson
A1 - J.-J. Wang
A1 - J.F. Scott
A1 - L.W. Martin
A1 - Ramamoorthy Ramesh
A1 - L.-Q. Chen
KW - Article
KW - competition
KW - Crystal lattices
KW - Ferroelectric superlattice
KW - ferroelectricity
KW - Geometric length
KW - Neodymium compounds
KW - Phase-field simulation
KW - Polar vortex
KW - Polarization
KW - simulation
KW - Superconducting materials
KW - Topological structure
KW - Topology
KW - Vortex flow
AB - A novel mesoscale state comprising of an ordered polar vortex lattice has been demonstrated in ferroelectric superlattices of PbTiO3/SrTiO3. Here, we employ phase-field simulations, analytical theory, and experimental observations to evaluate thermodynamic conditions and geometric length scales that are critical for the formation of such exotic vortex states. We show that the stability of these vortex lattices involves an intimate competition between long-range electrostatic, long-range elastic, and short-range polarization gradient-related interactions leading to both an upper and a lower bound to the length scale at which these states can be observed. We found that the critical length is related to the intrinsic domain wall width, which could serve as a simple intuitive design rule for the discovery of novel ultrafine topological structures in ferroic systems. © 2017 American Chemical Society.
PB - American Chemical Society
VL - 17
N1 - cited By 36
ER -