Plasmons in semiconductor and topological insulator wires with large dielectric constant
Yi Huang, Chao-Hsiang Sheu, and B. I. Shklovskii
School of Physics and Astronomy, University of Minnesota, Minneapolis, Minnesota 55455, USA
Received February 9, 2022, published online April 25, 2022
The dispersion law of plasmons running along thin wires with radius a is known to be practically linear. We show that in wires with a dielectric constant κ much larger than that of its environment κe, such dispersion law crosses over to a dispersionless three-dimensional-like law when the plasmon wavelength becomes shorter than the length (a/2)√ ̅κ̅/̅κ̅e̅l̅n̅(̅κ̅/̅2̅κ̅e̅)̅ at which the electric field lines of a point charge exit from the wire to the environment. This happens both in trivial semiconductor wires and wires of three-dimensional topological insulators.
Key words: plasmon dispersion law, dielectric constant, semiconductor and topological insulator wires.