Pulse-Driven Reconfiguration of Fractional Polar Topology in Zr-Substituted Barium Titanate

TL;DR

This study demonstrates through simulations that fractional polar topologies in Zr-substituted barium titanate nanodomains can be reconfigured using ultrafast electric pulses, revealing potential for multistate ferroelectric devices.

Contribution

It introduces a method to reconfigure fractional topological charges in ferroelectric nanodomains via local electric excitation, a novel approach in ferroelectric topology control.

Findings

Nanodomain texture stabilized by chemical doubling along the polar axis.

Electric pulses can induce metastable reconfigured topological states.

Programmed states are stable over at least 1 nanosecond in simulations.

Abstract

Polar topological textures in ferroelectrics can host internal structure beyond a single integer topological charge. Here, effective-Hamiltonian molecular-dynamics simulations are used to examine whether such internal fractional topology can be reconfigured by local electric excitation in ordered 12.5% Zr-substituted barium titanate. Chemical doubling along the polar axis stabilizes a coupled nanodomain texture consisting of alternating Q = -2 antiskyrmionic and Q = +4 skyrmionic slices, in which the local topological charge fragments into six -1/3 and six +2/3 localized contributions, denoted here as topological quarks, separated by Bloch-point-like singular conversion regions. Picosecond local electric-field pulses applied to selected vortex-core columns drive reconfiguration of the internal dipolar texture of a 2.6 nm nanodomain. Under a binary pulse-mask protocol addressing the six vortex cores, all 64 masks lead, within the chosen low-temperature simulation protocol, to distinct relaxed metastable configurations. The switching calculations are performed in a cryogenic regime, and the programmed states remain stable over at least 1 ns of field-free evolution on the simulation timescale. The resulting configurations are distinguishable both by sector-resolved topological fingerprints and by their real-space polarization fields. These results provide a computational proof of concept that fractional polar topology in a ferroelectric nanodomain can be locally reconfigured by ultrafast electric excitation and used as a multistate configurational degree of freedom in an idealized low-temperature setting.