Exact theory of edge diffraction and launching of transverse electric plasmons at two-dimensional junctions

TL;DR

This paper provides an exact analytical solution for electromagnetic wave diffraction at 2D electron system junctions, revealing how TE plasmons are excited and behave depending on edge type and impedance.

Contribution

It introduces an exact theoretical framework for edge diffraction and plasmon launching in 2D electron systems, including explicit power law behaviors.

Findings

Electric field at the edge varies with edge type, tending to zero or a finite value.

TE plasmons are excited with amplitudes depending on 2D system impedance.

Plasmon amplitude peaks at certain impedance values, then diminishes following derived power laws.

Abstract

An exact solution for electromagnetic wave diffraction at the junction of two-dimensional electron systems (2DES) is obtained and analyzed for electric field polarized along the edge. A special emphasis is paid to the metal-contacted and terminated edges. In the former case, electric field at the edge tends to zero; in the latter case, it tends to a finite value which is screened by 2d system in an anomalous fashion. For both types of edge and capacitive type of 2d conductivity, an incident wave excites transverse electric 2d plasmons. The amplitude of excited TE plasmons is maximized and becomes order of incident wave amplitude for capacitive impedance of 2DES order of free space impedance. For both large and small 2DES impedance, the amplitude of TE plasmons tends to zero according to the power laws which are explicitly derived.