P 21326-N16 Direct Simulation of Quantum Transport in Semiconductors
 
Project
Abstract
Scientists/Scholars
Project Publications
Further Activities
Cooperations
Final Report

Final Report English

The overall goal of this project was to investigate the influence of quantum phenomena on the carrier transport in nanoscaled semiconductor devices. To this aim, we developed new quantum transport models and deterministic methods for their solution. Main emphasis was put on the application of the Wigner-Weyl formalism and the two-band Wigner model. Since graphene appears as a very interesting candidate for future electronic devices, we used this new two-dimensional material as test object for our models. For the purpose of comparison we also developed a new semi-classical transport model based on the Boltzmann equation to study the coupled electron-phonon dynamics in graphene.

A further very important topic concerns the spin-induced phenomena that affect the carrier transport. These phenomena arise when electrons move through a magnetic environment, such that its magnetic moment, the spin, may interact with the surroundings. The pure quantum nature of spin requires transport models that deal with effects like quantum coherence, entanglement and quantum dissipation. For this purpose, we developed novel spin transport models from basic principles and numerical algorithms for their solution.

The following goals were achieved:

  1. Derivation of an effective classical Liouville-like evolution equation for the quantum phase space dynamics [1].
  2. A WKB-like asymptotic expansion of the multiband Wigner function designed to describe the dynamics in semiconductor devices in presence of the conduction band-to-valence band tunneling [2].
  3. Development of a semiclassical kinetic model for the coupled high-field transport of electrons and phonons in graphene [3].
  4. Development of a pseudo-spin phase space approach based on the Wigner-Weyl formalism for the ballistic transport of electrons in graphene [4], [5], [6], [7].
  5. Proposition of a new perturbation theory in terms of a generalized phase space quantization procedure [8].
  6. Study of the ion-spin relaxation mediated by spin exchange mechanisms [9].
  7. Setting up a matrix Boltzmann equation that incorporates spin-dependent scattering rates [10].
  8. Investigation of the non-Markovian quantum dynamics from environmental relaxation.amics [11].
  9. Study of the time evolution of spin densities in a two-dimensional electron gas subjected to Rashba spin-orbit coupling [12].

The cited references refer to list of Project Publications.

 

 
 
 

With support from
FWFDer Wissenschaftsfonds