Dynamic magnetic phase transition induced by parametric magnon pumping

Creators: Shan, Jun-Yi; Curtis, Jonathan B.; Guo, Mingyao; Roh, Chang Jae; Rotundu, C. R.; Lee, Young S.; Narang, Prineha; Noh, Tae Won; Demler, Eugene; Hsieh, D.¹

1. California Institute of Technology

Abstract

Uncovering pathways to optically drive magnetic order-disorder transitions on ultrashort timescales can lead to the realization of novel out-of-equilibrium quantum phenomena. A long-sought pathway is to directly excite a highly nonthermal energy-momentum distribution of magnons, bypassing both charge and lattice degrees of freedom. However, this remains elusive owing to the weak coupling and large momentum mismatch between photons and magnons. Here we demonstrate strong parametric excitation of magnons across the entire Brillouin zone of the antiferromagnetic insulator ${Sr₂} {Cu₃} {O₄} {Cl}_{₂}$ by periodically modulating the superexchange interaction with the electric field of light. The excitation efficiency is greatly enhanced by tuning to the van Hove singularity in the magnon spectrum, sufficient to transiently collapse the antiferromagnetic state using a pulsed laser field of ${10⁹}$ V/m. The order parameter recovery timescale increases by over 1000 times as a function of excitation density, reflecting a crossover from high- to low-energy magnon dominated decay dynamics. This electric-field induced parametric magnon pumping mechanism is applicable to a broad range of magnetic insulators and opens up the possibility of dynamically engineering magnon distributions by design.

Copyright and License

Acknowledgement

We acknowledge discussions with P. A. Lee, K. L. Seyler, M. Ye, and L. Balents. This work is funded by ARO MURI Grant No. W911NF-16-1-0361 and the Brown Investigator Award, a program of the Brown Science Foundation. D.H. also acknowledges support for instrumentation from the Institute for Quantum Information and Matter, an NSF Physics Frontiers Center (PHY-1733907). E.D. acknowledges support from the SNSF project 200021_212899, and from the ARO grant “Control of Many-Body States Using Strong Coherent Light-Matter Coupling in Terahertz Cavities.” C.J.R. and T.W.N. acknowledge support from the Institute for Basic Science in Korea (Grant No. IBS-R009-D1). J.B.C. and P.N. acknowledge support from the DOE-QIS program (DE-SC0022277) and from the Quantum Science Center (QSC), a National Quantum Information Science Research Center of the U.S. Department of Energy (DOE). P.N. gratefully acknowledges support from the Gordon and Betty Moore Foundation grant number GBMF8048 and from the John Simon Guggenheim Memorial Foundation (Guggenheim Fellowship in Physics). The work at Stanford and SLAC in the Stanford Institute for Materials and Energy Sciences (SIMES) was supported by the U.S. Department of Energy (DOE), Office of Science, Basic Energy Sciences (BES), Materials Sciences and Engineering Division, under Contract No. DE-AC02-76SF00515.

Files

PhysRevB.109.054302.pdf

Files (2.0 MB)

Name	Size	Download all
PhysRevB.109.054302.pdf md5:6467c3ecd708ac6bd59be8c30d6f549f	1.1 MB	Preview Download
SI_PRB_v3.pdf md5:77c652f3b56bcda5543709e88cfa48d7	834.4 kB	Preview Download

Additional details

	All versions	This version
Views	0	0
Downloads	0	0
Data volume	0 Bytes	0 Bytes