Subterahertz collective dynamics of polar vortices

Qian Li, Vladimir A. Stoica, Marek Paściak, Yi Zhu, Yakun Yuan, Tiannan Yang, Margaret R. McCarter, Sujit Das, Ajay K. Yadav, Suji Park, Cheng Dai, Hyeon Jun Lee, Youngjun Ahn, Samuel D. Marks, Shukai Yu, Christelle Kadlec, Takahiro Sato, Matthias C. Hoffmann, Matthieu Chollet, Michael E. KozinaSilke Nelson, Diling Zhu, Donald A. Walko, Aaron M. Lindenberg, Paul G. Evans, Long Qing Chen, Ramamoorthy Ramesh, Lane W. Martin, Venkatraman Gopalan, John W. Freeland, Jirka Hlinka, Haidan Wen

Research output: Contribution to journalArticlepeer-review

6 Scopus citations

Abstract

The collective dynamics of topological structures1–6 are of interest from both fundamental and applied perspectives. For example, studies of dynamical properties of magnetic vortices and skyrmions3,4 have not only deepened our understanding of many-body physics but also offered potential applications in data processing and storage7. Topological structures constructed from electrical polarization, rather than electron spin, have recently been realized in ferroelectric superlattices5,6, and these are promising for ultrafast electric-field control of topological orders. However, little is known about the dynamics underlying the functionality of such complex extended nanostructures. Here, using terahertz-field excitation and femtosecond X-ray diffraction measurements, we observe ultrafast collective polarization dynamics that are unique to polar vortices, with orders-of-magnitude higher frequencies and smaller lateral size than those of experimentally realized magnetic vortices3. A previously unseen tunable mode, hereafter referred to as a vortexon, emerges in the form of transient arrays of nanoscale circular patterns of atomic displacements, which reverse their vorticity on picosecond timescales. Its frequency is considerably reduced (softened) at a critical strain, indicating a condensation (freezing) of structural dynamics. We use first-principles-based atomistic calculations and phase-field modelling to reveal the microscopic atomic arrangements and corroborate the frequencies of the vortex modes. The discovery of subterahertz collective dynamics in polar vortices opens opportunities for electric-field-driven data processing in topological structures with ultrahigh speed and density.

Original languageEnglish (US)
Pages (from-to)376-380
Number of pages5
JournalNature
Volume592
Issue number7854
DOIs
StatePublished - Apr 15 2021

All Science Journal Classification (ASJC) codes

  • General

Fingerprint

Dive into the research topics of 'Subterahertz collective dynamics of polar vortices'. Together they form a unique fingerprint.

Cite this