[PDF] Electron Transport In Molecular Wires eBook

Author : Hugh Dalgleish
Publisher :
Page : 0 pages
File Size : 19,8 MB
Release : 2006
Category : Electron transport
ISBN :

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A molecular wire is an organic molecule that forms a conducting bridge between electronic contacts. Single molecules are likely to be the smallest entities to conduct electricity and thus molecular wires present many interesting challenges to fundamental science as well as enormous potential for nanoelectronic technological applications. A particular challenge stems from the realization that the properties of molecular wires are strongly influenced by the Combined characteristics of the molecule and the metal contacts. While gold has been the most studied contact material to date, interest in molecular wires with transition metal contacts that ar e electronically more complex than gold is growing. This thesis presents a theoretical investigation of electron transport and associated phenomena in molecular wires with transition metal contacts. An appropriate methodology is developed on the basis of Landauer theory and Ab initio and semi-empirical considerations and new, physically important systems are identified. Spin-dependent transport mechanisms and device characteristics are explored for molecular wires with ferromagnetic iron contacts, systems that have not been considered previously, either theoretically or experimentally. Electron transport between iron point contacts bridged by iron atoms is also investigated. Spin-dependent transport is also studied for molecules bridging nickel contacts and a possible explanation of some experimentally observed phenomena is proposed. A novel physical phenomenon termed Strong spin current rectification and a new controllable negative differential resistance mechanism with potential applications for molecular electronic technology are introduced. The phenomena predicted in this thesis should be accessible to present day experimental techniques and this work is intended to stimulate experiments directed at observing them.

Author : Peter Rodgers
Publisher : World Scientific
Page : 367 pages
File Size : 47,76 MB
Release : 2009-08-21
Category : Technology & Engineering
ISBN : 9814466867

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This book contains 35 review articles on nanoscience and nanotechnology that were first published in Nature Nanotechnology, Nature Materials and a number of other Nature journals. The articles are all written by leading authorities in their field and cover a wide range of areas in nanoscience and technology, from basic research (such as single-molecule devices and new materials) through to applications (in, for example, nanomedicine and data storage).

Author : Laurens D. A. Siebbeles
Publisher : John Wiley & Sons
Page : 293 pages
File Size : 39,43 MB
Release : 2011-07-18
Category : Technology & Engineering
ISBN : 352763309X

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As functional elements in opto-electronic devices approach the singlemolecule limit, conducting organic molecular wires are the appropriate interconnects that enable transport of charges and charge-like particles such as excitons within the device. Reproducible syntheses and a thorough understanding of the underlying principles are therefore indispensable for applications like even smaller transistors, molecular machines and light-harvesting materials. Bringing together experiment and theory to enable applications in real-life devices, this handbook and ready reference provides essential information on how to control and direct charge transport. Readers can therefore obtain a balanced view of charge and exciton transport, covering characterization techniques such as spectroscopy and current measurements together with quantitative models. Researchers are thus able to improve the performance of newly developed devices, while an additional overview of synthesis methods highlights ways of producing different organic wires. Written with the following market in mind: chemists, molecular physicists, materials scientists and electrical engineers.

Author :
Publisher :
Page : pages
File Size : 25,89 MB
Release : 2004
Category :
ISBN :

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The electron transport through a molecular wire under the influence of an external laser field is studied using a reduced density matrix formalism. The full system is partitioned into the relevant part, i.e. the wire, electron reservoirs and a phonon bath. An earlier second-order perturbation theory approach of Meier and Tannor for bosonic environments which employs a numerical decomposition of the spectral density is used to describe the coupling to the phonon bath and is extended to deal with the electron transfer between the reservoirs and the molecular wire. Furthermore, from the resulting time-nonlocal (TNL) scheme a time-local (TL) approach can be determined. Both are employed to propagate the reduced density operator in time for an arbitrary time-dependent system Hamiltonian which incorporates the laser field non-perturbatively. Within the TL formulation, one can extract a current operator for the open quantum system. This enables a more general formulation of the problem which is necessary to employ an optimal control algorithm for open quantum systems in order to compute optimal control fields for time-distributed target states, e.g. current patterns. Thus, we take a fundamental step towards optimal control in molecular electronics. Numerical examples of the population dynamics, laser controlled current, TNL vs. TL and optimal control fields are presented to demonstrate the diverse applicability of the derived formalism.