Research Highlight | Materials Science

Imprinting topological defects in electron waves using magnetic charge
In a study published in Nano Letters, researchers experimentally show that excitations or defects carrying magnetic charge in artificial spin ices introduce a topological defect in incident coherent electron waves.
Imprinting topological defects in electron waves using magnetic charge image
(a–c) Experimentally recovered magnetic induction color maps for nodes with 3, 5, and 6 interacting bars, respectively. (d–f) The corresponding far-field diffraction patterns showing the presence of localized vortex states at the center of the nodes as well as ends of the magnetic bars.

Scientific Achievement

We created of localized electron vortex states by magnetic monopole excitations in artificial spin ices.

Significance and Impact

Creation and manipulation structured quantum electron waves will enable novel imaging and quantum scattering experiments, in particular for exploring chiral materials

Research Details

  • The artificial spin ice lattice consisted of closely-spaced CoFe islands (size 2 µm X 160 nm and thickness 25 nm).
  • Using Lorentz TEM we showed the presence of localized electron vortex states carrying orbital angular momentum imprinted into electron waves at the location of magnetic monopole excitation.
  • Using off-axis holography, we showed a direct correspondence between the magnitude and sign of the magnetic charge of the monopole excitation, and the orbital angular momentum imparted to the electron beam.

DOI: 10.1021/acs.nanolett.8b02915

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