Abstract
Recently, a layered ferroelectric CuInP2Se6 was shown to exhibit domain walls with locally enhanced piezoresponse - a striking departure from the observations of nominally zero piezoresponse in most ferroelectrics. Although it was proposed that such "bright"domain walls are phase boundaries between ferri- and antiferroelectrically ordered regions of the materials, the physical mechanisms behind the existence and response of these boundaries remain to be understood. Here, using Landau-Ginzburg-Devonshire phenomenology combined with a four sublattices model, we describe quantitatively the bright-contrast and dark-contrast domain boundaries between the antiferroelectric, ferroelectric, or ferrielectric long-range-ordered phases in a layered ferroelectric-antiferroelectric ferroics, such as CuInP2(S1-ySey)6.
| Original language | English |
|---|---|
| Article number | 174108 |
| Journal | Physical Review B |
| Volume | 102 |
| Issue number | 17 |
| DOIs | |
| State | Published - Nov 17 2020 |
Funding
Using low-temperature PFM, the coexistence of piezoelectric and nonpiezoelectric phases separated by unusual bright domain walls with enhanced piezoelectric response has been revealed in , and explained by enhanced piezoresponse at the FE(FEI)-AFE phase boundary [see Fig. ]. The AFE state was partially polarized, with inclusions of structurally different FEI domains enclosed by the “enhanced” phase boundaries, which indicates the coexistence of AFE, FEI, and FE-AFE phases, and the conclusion was supported by optical spectroscopies and DFT calculations as detailed in Ref. . The layered ferroelectric only revealed a dark domain by comparison [see Fig. ].