Vector, Bidirector and Bloch Skyrmion Phases Induced by Structural Crystallographic Symmetry Breaking

TL;DR

This paper explores how structural symmetry breaking in various phases induces vector, bidirector, and Bloch Skyrmion phases, extending magnetic Skyrmion theory to ferroelectric materials through symmetry analysis and Ginzburg Landau functional.

Contribution

It introduces a framework linking crystallographic symmetry breaking to Skyrmion phases in ferroelectric and nonferroelastic materials, applying phenomenological theory to new classes of materials.

Findings

Identification of vector and bidirector order parameters in symmetry-broken phases

Extension of Skyrmion theory to ferroelectric materials

Proposal of a Ginzburg Landau functional with chiral bidirector symmetry

Abstract

The 212 species of structural phase transitions which break macroscopic symmetry are analyzed with respect to the occurrence of time-reversal invariant vector and bidirector order parameters. The possibility of discerning the orientational domain states of the low-symmetry phase by these `vectorlike' physical properties has been derived using a computer algorithm exploiting the concept of polar, axial, chiral and neutral dipoles. It is argued that for species 32 > 3, 422 > 4 and 622 > 6, Bogdanov-Yablonskii phenomenological theory for a ferromagnetic Bloch Skyrmions applies also to the ferroelectric Bloch Skyrmions. In these fully-ferroelectric and nonferroelastic species, the Ginzburg Landau functional allows a pseudo-Lifshitz invariant of chiral bidirector symmetry, analogous to the chiral Dzyaloshinskii-Moria term assumed in magnetic Bloch Skyrmion theory.