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Ultrafast enhancement of ferromagnetic spin exchange induced by ligand-to-metal charge transfer

Ron, A. and Chaudhary, Swati and Zhang, G. and Ning, H. and Zoghlin, E. and Wilson, S. D. and Averitt, R. D. and Refael, G. and Hsieh, D. (2019) Ultrafast enhancement of ferromagnetic spin exchange induced by ligand-to-metal charge transfer. . (Unpublished)

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Directly modifying spin exchange energies in a magnetic material with light can enable ultrafast control of its magnetic states. Current approaches rely on tuning charge hopping amplitudes that mediate exchange by optically exciting either virtual or real charge-transfer transitions (CT) between magnetic sites. Here we show that when exchange is mediated by a non-magnetic ligand, it can be substantially enhanced by optically exciting a real CT transition from the ligand to magnetic site, introducing lower order virtual hopping contributions. We demonstrate sub-picosecond enhancement in a superexchange dominated ferromagnet CrSiTe3 through this mechanism using phase-resolved coherent phonon spectroscopy. This technique can also be applied in the paramagnetic phase to disentangle light induced exchange modification from other ultrafast effects that alter the magnetization. This protocol can potentially be broadly applied to engineer thermally inaccessible spin Hamiltonians in superexchange dominated magnets.

Item Type:Report or Paper (Discussion Paper)
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URLURL TypeDescription Paper
Ron, A.0000-0002-1840-7824
Hsieh, D.0000-0002-0812-955X
Additional Information:This work was supported by ARO MURI Grant No. W911NF-16-1-0361. D.H. and G.R also acknowledge support from the David and Lucile Packard Foundation. D.H. acknowledges support for instrumentation from the Institute for Quantum Information and Matter, an NSF Physics Frontiers Center (PHY-1733907). A.R. acknowledges support from the Caltech Prize Fellowship. The MRL Shared Experimental Facilities are supported by the MRSEC Program of the NSF under Award No. DMR 1720256; a member of the NSF-funded Materials Research Facilities Network. S.D.W authors acknowledge support from the Nanostructures Cleanroom Facility at the California NanoSystems Institute (CNSI). G.R. also acknowledges partial support through DOE grant no. DE-SC0019166. Author contributions: A.R. and D.H. planned the experiment. A.R., H. N and G.Z. performed the measurements. A.R., G.Z., R.D.A. and D.H. analyzed the data. S.C. and G.R. performed the theoretical calculations. E.Z. and S.D.W. prepared and characterized the samples. A.R., S.C. and D.H. wrote the manuscript.
Group:UNSPECIFIED, Institute for Quantum Information and Matter
Funding AgencyGrant Number
Army Research Office (ARO)W911NF-16-1-0361
David and Lucile Packard FoundationUNSPECIFIED
Institute for Quantum Information and Matter (IQIM)UNSPECIFIED
Department of Energy (DOE)DE-SC0019166
Record Number:CaltechAUTHORS:20191217-085020547
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Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:100322
Deposited By: Tony Diaz
Deposited On:17 Dec 2019 18:06
Last Modified:04 Jun 2020 10:14

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