Frustration and Self-Ordering of Topological Defects in Ferroelectrics

Atomic imaging of mechanically induced topological transition of ferroelectric vortices

“…These findings provide new pathways to control the exotic topological ferroelectric structures for future nanoelectronics and also valuable insights into understanding of lattice-charge interactions at nanoscale. 3 Ferroelectric vortices composed of electric dipole moments with continuous rotation are theoretically predicted to occur in nanostructures such as nanowires 5 , nanodots 6 and nanocomposites 7 and have been experimentally realized in rhombohedral BiFeO3 [8][9][10][11] , tetragonal PbZr0.2Ti0.8O3 12 thin films, and PbTiO3/SrTiO3 (PTO/STO) superlattices 3 . These polarization vortex states that are regarded as topological defects and can be characterized by an electric toroidal moment, can exist over a few nanometers, making them a perfect candidate for data storage applications 13 , as their storage capacity can reach~10 12 bits per square inch with little cross-talk between adjacent bits, which is several orders of magnitude larger than the current technology of ferroelectric storages 1 .…”

Topological Defects with Distinct Dipole Configurations in PbTiO3/SrTiO3 Multilayer Films

“…Differently, in our multilayer systems, we used cubic STO as the substrate, which favors the c-axis-orientated PTO film with tetragonal structure. According to the effects of finite-temperature fluctuations, topological point defects, such as hedgehog-and antihedgehog-like configurations [49], are highly expected in a tetragonal state. Indeed, and as indicated above, the observed dipole configurations (small green ellipses in Fig.…”

Ferroelectric phase-transition frustration near a tricritical composition point

“…Geometric frustration depicts an intrinsic incompatibility of some fundamental interactions with respect to the underlying lattice geometry. Stimulated by this, a plethora of unusual phenomena and intriguing effects have been reported, e.g., spin liquids and spin ice 13 , glass-to-crystalline transitions 14 , and exotic spiral ferroelectric states 15 , 16 . Given their commonality in phenomenological abnormality about PhT, a potential competition between the first- and second-order transitions at the tricritical point of ferroelectric Pb(Zr 1− x Ti x )O 3 (PZT, x ≥ 0.50) is investigated in this work.…”