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arXiv · 2203.03522

Melting of Polarization Vortices Crystals and Chiral Phase Transitions in Oxide Superlattices

Fernando Gómez-Ortiz·Pablo García-Fernández·Juan M. López·Javier Junquera
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Abstract

We study the equilibrium arrangements of polarization vortices in (PbTiO$_3$)$_n$/(SrTiO$_3$)$_n$ superlattices by means of second-principles simulations. We find that, at low temperatures, polarization vortices organize in a regular arrangement in which clockwise and counter-clockwise vortices alternate positions, leading to a crystal-like structure with well defined handedness. This chiral crystal melts at a critical temperature $T_\mathrm{M}$ into a chiral liquid, where long-range order is lost but handedness is preserved. At even higher temperatures, $T_\mathrm{C}$, a second phase transition occurs, at which the chiral liquid of polarization vortices loses its handedness. Both phase transitions can be readily identified by the adequate choices of order parameters.

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Fernando Gómez-Ortiz, Pablo García-Fernández, Juan M. López, Javier Junquera. 2022-03-07. Melting of Polarization Vortices Crystals and Chiral Phase Transitions in Oxide Superlattices. https://doi.org/10.1103/physrevb.105.l220103

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