Light-Driven Spontaneous Phonon Chirality and Magnetization in Paramagnets

Yafei Ren, Mark Rudner, and Di Xiao

Phys. Rev. Lett. 132, 096702 – Published 28 February 2024

Abstract

Spin-phonon coupling enables the mutual manipulation of phonon and spin degrees of freedom in solids. In this study, we reveal the inherent nonlinearity within this coupling. Using a paramagnet as an illustration, we demonstrate the nonlinearity by unveiling spontaneous symmetry breaking under a periodic drive. The drive originates from linearly polarized light, respecting a mirror reflection symmetry of the system. However, this symmetry is spontaneously broken in the steady state, manifested in the emergence of coherent chiral phonons accompanied by a nonzero magnetization. We establish an analytical self-consistency equation to find the parameter regime where spontaneous symmetry breaking occurs. Furthermore, we estimate realistic parameters and discuss potential materials that could exhibit this behavior. Our findings shed light on the exploration of nonlinear phenomena in magnetic materials and present possibilities for on-demand control of magnetization.

Received 27 July 2023
Revised 13 November 2023
Accepted 25 January 2024

DOI:https://doi.org/10.1103/PhysRevLett.132.096702

Physics Subject Headings (PhySH)

Bifurcations Coherent control Light-induced magnetic effects Optical phonons Spin-phonon coupling Ultrafast magnetic effects Ultrafast phenomena

Paramagnets

Condensed Matter, Materials & Applied PhysicsNonlinear DynamicsAtomic, Molecular & Optical

Authors & Affiliations

Yafei Ren ^1,2, Mark Rudner ³, and Di Xiao ^1,3

¹Department of Materials Science and Engineering, University of Washington, Seattle, Washington 98195, USA
²Department of Physics and Astronomy, University of Delaware, Newark, Delaware 19716, USA
³Department of Physics, University of Washington, Seattle, Washington 98195, USA