Quantum-transport theory for semiconductor nanostructures: A density-matrix formulation

TL;DR

This paper develops a comprehensive density-matrix framework for quantum transport in semiconductor nanostructures, enabling detailed analysis of scattering, coherence, and polaronic effects beyond conventional methods.

Contribution

It introduces a fully operatorial density-matrix formulation that distinguishes effects of adiabatic limits and reduction procedures, enhancing understanding of scattering superoperators in quantum transport.

Findings

Analysis of scattering superoperators at various description levels

Ability to study scattering-induced phase coherence in steady state

Investigation of polaronic effects in biased superlattices

Abstract

A general density-matrix formulation of quantum-transport phenomena in semiconductor nanostructures is presented. More specifically, contrary to the conventional single-particle correlation expansion, we shall investigate separately the effects of the adiabatic or Markov limit and of the reduction procedure. Our fully operatorial approach allows us to better identify the general properties of the scattering superoperators entering our effective quantum-transport theory at various description levels, e.g., N electrons-plus-quasiparticles, N electrons only, and single-particle picture. In addition to coherent transport phenomena characterizing the transient response of the system, the proposed theoretical description allows to study scattering induced phase coherence in steady-state conditions. As prototypical example, we shall investigate polaronic effects in strongly biased semiconductor superlattices.