Spontaneous chiral symmetry breaking in metamaterials

• Published in: Nature communications Vol. 5; no. 1; p. 4441
• Main Authors: Liu, Mingkai, Powell, David A., Shadrivov, Ilya V., Lapine, Mikhail, Kivshar, Yuri S.
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 18-07-2014; Nature Publishing Group
• Subjects: 639/301/1019/1015; 639/766/400; Humanities and Social Sciences; multidisciplinary; Science; Science (multidisciplinary)
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/ncomms5441

Spontaneous chiral symmetry breaking underpins a variety of areas such as subatomic physics and biochemistry, and leads to an impressive range of fundamental phenomena. Here we show that this prominent effect is now available in artificial electromagnetic systems, enabled by the advent of magnetoelastic metamaterials where a mechanical degree of freedom leads to a rich variety of strong nonlinear effects such as bistability and self-oscillations. We report spontaneous symmetry breaking in torsional chiral magnetoelastic structures where two or more meta-molecules with opposite handedness are electromagnetically coupled, modifying the system stability. Importantly, we show that chiral symmetry breaking can be found in the stationary response of the system, and the effect is successfully demonstrated in a microwave pump-probe experiment. Such symmetry breaking can lead to a giant nonlinear polarization change, energy localization and mode splitting, which provides a new possibility for creating an artificial phase transition in metamaterials, analogous to that in ferrimagnetic domains.
Spontaneous symmetry breaking is one of the unusual effects offered by nonlinear metamaterials. Here, the authors study this effect in chiral magnetoelastic metamaterials where the meta-molecules of opposite handedness are both electromagnetically and mechanically coupled.