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Pure chiral polar vortex phase in PbTiO3/SrTiO3 superlattices with tunable circular dichroism

Abstract: Nontrivial polarization textures have been demonstrated in ferroelectric/dielectric superlattices, where the electrostatic, elastic, and different gradient energies compete in a delicate balance. When PbTiO3/SrTiO3 superlattices are grown on DyScO3, the coexistence of ferroelectric domains and vortex structure is observed for n = 12-20 unit cells. Here, we report an approach to achieve single-phase vortex structures in superlattices by controlling the epitaxial strain using Sr1.04Al0.12Ga0.35Ta0.50O3 substrates. The domain width follows Kittel's law with the thickness of the ferroelectric PbTiO3 layers. A phase transition from vortex to a disordered phase with temperature is characterized by the correlation length. Resonant soft X-ray diffraction circular dichroism at the titanium L-edge reveals enhanced chirality with the thickness of the ferroelectric layer. These results are supported by second-principles simulations, which demonstrate that the integrated helicity increases with n. The stabilization of chiral single-phase polar vortices in ferroelectric/dielectric superlattices can enable novel optoelectronic devices with enhanced ferroelectric-light interaction.

 Autoría: Das S., McCarter M.R., Gómez-Ortiz F., Tang Y.L., Hong Z., Ghosh A., Shafer P., García-Fernández P., Junquera J., Martin L.W., Ramesh R.,

 Fuente: Nano Letters, 2023, 23(14), 6602-6609

 Editorial: American Chemical Society

 Fecha de publicación: 01/07/2023

 Nº de páginas: 8

 Tipo de publicación: Artículo de Revista

 DOI: 10.1021/acs.nanolett.3c01744

 ISSN: 1530-6984,1530-6992

 Proyecto español: PGC2018-096955-B-C41

 Url de la publicación: https://doi.org/10.1021/acs.nanolett.3c01744

Autoría

DAS, SUJIT

MCCARTER, MARGARET R.

FERNANDO GOMEZ ORTIZ

TANG, YUN-LONG

HONG, ZIJIAN

SHAFER, PADRAIC

MARTIN, LANE W.

RAMESH, RAMAMOORTHY