Controlling spins with surface magnon polaritons
Name
PhysRevB.100.235453.pdf
Description
Published version
Size
2.64 MB
Format
Adobe PDF
Checksum (MD5)
515703d4fdb8c3f9d0d12d09359f1ce2
Author(s)
Sloan, Jamison
Rivera, Nicholas
Joannopoulos, John D
Kaminer, Ido
Soljačić, Marin
Date Issued
2019
Journal
Physical Review B
Publisher
American Physical Society (APS)
Version
Final published version
Abstract
© 2019 American Physical Society. Polaritons in metals, semimetals, semiconductors, and polar insulators can allow for extreme confinement of electromagnetic energy, providing many promising opportunities for enhancing typically weak light-matter interactions such as multipolar radiation, multiphoton spontaneous emission, Raman scattering, and material nonlinearities. These extremely confined polaritons are quasielectrostatic in nature, with most of their energy residing in the electric field. As a result, these "electric" polaritons are far from optimized for enhancing emission of a magnetic nature, such as spin relaxation, which is typically many orders of magnitude slower than corresponding electric decays. Here, we take concepts of "electric" polaritons into magnetic materials, and propose using surface magnon polaritons in negative magnetic permeability materials to strongly enhance spin relaxation in nearby emitters. Specifically, we provide quantitative examples with MnF2 and FeF2, enhancing spin transitions in the THz spectral range. We find that these magnetic polaritons in 100-nm thin films can be confined to lengths over 10 000 times smaller than the wavelength of a photon at the same frequency, allowing for a surprising 12 orders of magnitude enhancement in magnetic dipole transitions. This takes THz spin-flip transitions, which normally occur at timescales on the order of a year, and forces them to occur at sub-ms timescales. Our results suggest an interesting platform for polaritonics at THz frequencies, and more broadly, a way to use polaritons to control light-matter interactions.
MIT Department
Massachusetts Institute of Technology. Research Laboratory of Electronics
Massachusetts Institute of Technology. Department of Physics
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Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use.
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DOI of Published Version
10.1103/PHYSREVB.100.235453
