Microscopic derivation of transport coefficients and boundary conditions in discrete drift-diffusion models of weakly coupled superlattices

TL;DR

This paper derives a discrete drift-diffusion model from microscopic tunneling models for weakly coupled superlattices, providing realistic transport coefficients and boundary conditions to understand current oscillations.

Contribution

It introduces a microscopic derivation of transport coefficients and boundary conditions for discrete models of superlattices, linking microscopic parameters to macroscopic behavior.

Findings

Realistic transport coefficients are calculated from microscopic expressions.

Novel contact current-field characteristic curves are introduced.

Conditions for self-sustained current oscillations are clarified.

Abstract

A discrete drift-diffusion model is derived from a microscopic sequential tunneling model of charge transport in weakly coupled superlattices provided temperatures are low or high enough. Realistic transport coefficients and novel contact current--field characteristic curves are calculated from microscopic expressions, knowing the design parameters of the superlattice. Boundary conditions clarify when possible self-sustained oscillations of the current are due to monopole or dipole recycling.