Quantum model of coupled intersubband plasmons

TL;DR

This paper introduces a quantum model to analyze dipole-dipole coupling in semiconductor quantum wells, revealing how collective electron excitations form bright modes influenced by Coulomb interactions and tunneling effects.

Contribution

The paper presents a novel quantum framework for calculating intersubband plasmon coupling, incorporating microscopic current overlaps and collective mode formation.

Findings

Coupling depends on microscopic current density overlap.

A sum rule for collective modes is derived.

Interplay between tunneling and Coulomb interaction affects absorption spectra.

Abstract

We present a quantum model to calculate the dipole-dipole coupling between electronic excitations in the conduction band of semiconductor quantum wells. We demonstrate that the coupling depends on a characteristic length, related to the overlap between microscopic current densities associated with each electronic excitation. As a result of the coupling, a macroscopic polarization is established in the quantum wells, corresponding to one or few bright collective modes of the electron gas. Our model is applied to derive a sum rule and to investigate the interplay between tunnel coupling and Coulomb interaction in the absorption spectrum of a dense electron gas.