Abstract:
|
We present theoretical simulations of electron refraction at the lateral atomic interface between a
“homogeneous” Cu(111) surface and the “nanostructured” one-monolayer (ML) Ag/Cu(111) dislocation
lattice. Calculations are performed for electron binding energies barely below the 1 ML Ag/
Cu(111) M-point gap (binding energy EB ¼53 meV, below the Fermi level) and slightly above its
C
-point energy (EB ¼160 meV), both characterized by isotropic/circular constant energy surfaces.
Using plane-wave-expansion and boundary-element methods, we show that electron refraction
occurs at the interface, the Snell law is obeyed, and a total internal reflection occurs beyond the
critical angle. Additionally, a weak negative refraction is observed for EB ¼53 meV electron
energy at beam incidence higher than the critical angle. Such an interesting observation stems from
the interface phase-matching and momentum conservation with the umklapp bands at the second
Brillouin zone of the dislocation lattice. The present analysis is not restricted to our Cu-Ag/Cu
model system but can be readily extended to technologically relevant interfaces with spinpolarized,
highly featured, and anisotropic constant energy contours, such as those characteristic
for Rashba systems and topological insulators. Published by AIP Publishing. |