“Chiral surface and edge plasmons in ferromagnetic conductors” by Giovanni Vignale (University of Missouri-Columbia)

Wednesday, May 16, 2018 - 4:00pm
Condensed Matter Physics Seminar

The recently introduced concept of ``surface Berry plasmons" is studied in
the concrete instance of a ferromagnetic conductor in which the Berry
curvature, generated by atomic spin-orbit (SO) interaction, has opposite
signs for carriers parallel or antiparallel to the magnetization. By using
collisionless hydrodynamic equations with appropriate boundary conditions,
we study both the surface plasmons of a three-dimensional ferromagnetic
conductor and the edge plasmons of a two-dimensional one. The anomalous
velocity and the broken inversion symmetry at the surface or the edge of the
conductor create a ``handedness", whereby the plasmon frequency depends not
only on the angle between the wave vector and the magnetization, but also on
the direction of propagation along a given line. In particular, we find that
the frequency of the edge plasmon depends on the direction of propagation
along the edge. These Berry curvature effects are compared and contrasted
with similar effects induced in the plasmon dispersion by an external
magnetic field in the absence of Berry curvature. We argue that Berry
curvature effects may be used to control the direction of propagation of the
surface plasmons, and thus create a link between plasmonics and spintronics.

PAB 4-330