Polar Topological Defects in Ferroelectric Nanostructures: Novel Features and Phenomena

About twenty years ago, electrical topological defects were predicted in ferroelectric nanostructures [1-3]. These fascinating objects are now forming one active and exciting research field, since they have the potential to revolutionize technologies but also yield striking phenomena (see, e.g., Refs. [4-7] and references therein).

The aim of this Talk is to reveal and explain, via the use of first-principle-based atomistic effective Hamiltonians and state-of-the-art experimental growth and characterization techniques, the emergence of novel features, all associated with polar topological states. This includes:
Their activation by THz pulses and twisted light [8-10],
Their role in creating magnetism in nominal non-magnetic systems [11],
The systematic control of their motions across thin films [10,12,13],
The unusual lattice vibrations and soft modes responsible for their condensation [14,15],
The transitions between different topological states [16-20], and
The occurrence of novel phases and phenomena, such as polar solitons in low-dimensional multiferroics [21], quantum-induced dipolar liquid states and quantum criticality [22] and electrical hopfions [23].

The authors at Arkansas thank the Vannevar Bush Faculty Fellowship (VBFF) from the Department of Defense, the MonArk NSF Quantum Foundry supported by the National Science Foundation Q-AMASE-I Program under NSF Award No.DMR-1906383, the ARO Grants No. W911NF-21-1-011 and W911NF-21-2-0162 (ETHOS), the DARPA Grant No. HR0011727183-D18AP00010 (TEE Program), and the ONR Grant N00014-21-1-2086. The research at University of New South Wales (UNSW) is supported by DARPA Grant No. HR0011727183-D18AP00010 (TEE Program), partially supported by the Australian Research Council Centre of Excellence in Future Low-Energy Electronics Technologies (project number CE170100039) and funded by the Australian Government.

References:
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[4] Vivasha Govinden et al., Nature Materials 22, 553-561 (2023).
[5] Javier Junquera, et al., Reviews of Modern Physics 95, 025001 (2023).
[6] Lu Han et al., Nature 603, 7899 (2022).
[7] Shuai Yuan et al., Physical Review Letters 130, 226801 (2023).
[8] Peng Chen et al., Physical Review B 107, L060101 (2023).
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[10] Lingyuan Gao et al., under review.
[11] Lingyuan Gao et al., Physical Review Letters, in press.
[12] Sukriti Mantri et al., under review.
[13] Sergei Prokhorenko et al., under review.
[14] Suyas Rijal et al., under review.
[15] Maxim A. Makeev et al., in preparation.
[16] Vivasha Govinden et al., Physical Review Materials 7, L011401 (2023).
[17] Vivasha Govinden et al., Physical Review Materials 5, 124205 (2021).
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[20] Qi Zhang et al., Advanced Materials 29,1702375 (2017).
[21] Vivasha Govinden et al., Nature Communications 14, 4178 (2023).
[22] W. Luo et al., under review.
[23] Suyash Rijal et al., in preparation.