Please use this identifier to cite or link to this item:
logo share SHARE logo core CORE BASE
Visualizar otros formatos: MARC | Dublin Core | RDF | ORE | MODS | METS | DIDL | DATACITE

A time-dependent approach to electron pumping in open quantum systems

AuthorsStefanucci, Gianluca; Kurth, S.; Rubio, Angel; Gross, E. K. U.
KeywordsBound states
Density functional theory
Electron density
Electron transport theory
Issue Date29-Feb-2008
PublisherAmerican Physical Society
CitationPhysical Review B 77: 75339 (2008)
AbstractWe use a recently proposed time-dependent approach to investigate the motion of electrons in quantum pump device configurations. The occupied one-particle states are propagated in real time and employed to calculate the local electron density and current. The approach can also be embedded in the framework of time-dependent density functional theory to include electron-electron interactions. An advantage of the present computational scheme is that the same computational effort is required to simulate monochromatic, polychromatic, and nonperiodic drivings. Furthermore, initial-state dependence and history effects are naturally accounted for. We present results for one-dimensional devices exposed to a traveling potential wave. (i) We show that for pumping across a single potential barrier, electrons are transported in pockets and the transport mechanism resembles pumping of water with the Archimedean screw; (ii) we propose a simple model to study pumping through semiconductor nanostructures and we address the phenomenon of the current flowing in the opposite direction to the field propagation; (iii) we present the first numerical evidence of long-lived superimposed oscillations as induced by the presence of bound states and discuss the dependence of their lifetime on the frequency and amplitude of the driving field. By combining Floquet theory with nonequilibrium Green's functions, we also obtain a general expression for the pumped current in terms of inelastic transmission probabilities. This latter result is used for benchmarking our propagation scheme in the long-time limit. Finally, we discuss the limitations of Floquet-based algorithms and suggest our approach as a possible way to go beyond them.
DescriptionPACS nrs.: 73.23.-b, 05.60.Gg, 72.10.-d, 73.63.-b
Publisher version (URL)
Appears in Collections:(CFM) Artículos

Files in This Item:
File Description SizeFormat
time-dependent approach.pdf587,67 kBAdobe PDFThumbnail
Show full item record
Review this work


checked on May 22, 2022


checked on May 22, 2022

Page view(s)

checked on May 25, 2022


checked on May 25, 2022

Google ScholarTM




WARNING: Items in Digital.CSIC are protected by copyright, with all rights reserved, unless otherwise indicated.