Discovery of Polarized Bloch Points in Ferroelectric Materials by Chinese Academy of Sciences

TapTechNews May 20th news, Chinese Academy of Sciences researchers have discovered polarized Bloch points (Blochpoint) in ferroelectric materials, which is a'singularity' in the vector field, and the vectors around it point in all directions in space.

This discovery is another important breakthrough of the research team in the topological domain structure of ferroelectric materials after the fully closed flux array, half-lattice, and periodic electric dipole waves.

The research team is composed of researcher Ma Xiuliang from the Institute of Physics, Chinese Academy of Sciences, researcher Wang Yujia from the Institute of Metal Research, Chinese Academy of Sciences, and associate researcher Feng Yanpeng from the Guangdong Songshan Lake Materials Laboratory. The relevant results were published online in Nature Communications.

Bloch points play an important role in processes such as the flipping of vortices and the formation and annihilation of skyrmions, and are a bridge between classical magnetism and quantum magnetism.

Based on the previous work of the half-lattice, the research team used phase-field simulation to construct a symmetric electrode model and found that as the electrode thickness increases, the convergent and divergent half-lattices evolve into two types of Bloch points respectively: one is in-plane convergent and out-of-plane divergent, and the other is in-plane divergent and out-of-plane convergent.

The team used pulsed laser deposition technology to grow an ultra-thin PbTiO3 film (5 nanometers) sandwiched by SrRuO3 electrodes on the SmScO3 substrate, and observed the planar and cross-sectional samples through aberration-corrected transmission electron microscopy, and observed polarized Bloch points with in-plane and out-of-plane divergent and convergent characteristics in the PbTiO3 film.

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