Simple electron-electron scattering in non-equilibrium Green's function simulations

TL;DR

This paper extends non-equilibrium Green's function simulations to include electron-electron interactions beyond Hartree-Fock using a simplified GW approach with the Single Plasmon Pole Approximation, applied to heterostructures.

Contribution

It introduces a novel method for incorporating electron-electron interactions in NEGF simulations using a simplified GW scheme for multi-subband systems.

Findings

Demonstrates the method on a four well quantum cascade laser

Provides insights into screening and plasmon dispersion in 2D and 3D systems

Shows comparison with experimental data for different doping levels

Abstract

In this work we include electron-electron interaction beyond Hartree-Fock level in our non-equilibrium Green's function approach by a crude form of GW through the Single Plasmon Pole Approximation. This is achieved by treating all conduction band electrons as a single effective band screening the Coulomb potential. We describe the corresponding self-energies in this scheme for a multi-subband system. In order to apply the formalism to heterostructures we discuss the screening and plasmon dispersion in both 2D and 3D systems. Results are shown for a four well quantum cascade laser with different doping concentration where comparisons to experimental findings can be made.