نتایج جستجو برای: landauer

تعداد نتایج: 880  

Journal: :Annals of the New York Academy of Sciences 2002
Giorgios Fagas Gianaurelio Cuniberti Klaus Richter

We discuss the conductance of a molecular bridge between mesoscopic electrodes supporting low-dimensional transport and bearing an internal structure. As an example for such nanoelectrodes we assume semi-infinite (carbon) nanotubes. In the Landauer scattering matrix approach, we show that the conductance of this hybrid is very sensitive to the geometry of the contact, unlike the usual behavior ...

Journal: :Physical review letters 2006
Norbert Nemec David Tománek Gianaurelio Cuniberti

We combine ab initio density functional theory with transport calculations to provide a microscopic basis for distinguishing between good and poor metal contacts to nanotubes. Comparing Ti and Pd as examples of different contact metals, we trace back the observed superiority of Pd to the nature of the metal-nanotube hybridization. Based on large scale Landauer transport calculations, we suggest...

Journal: :Physical review letters 2006
Michael Galperin Abraham Nitzan Mark A Ratner

Using a model comprising a two-level bridge connecting free electron reservoirs we show that coupling of a molecular bridge to electron-hole excitations in the leads can markedly effect the source-drain current through a molecular junction. In some cases, e.g., molecules that exhibit strong charge transfer transitions, the contribution from electron-hole excitations can exceed the Landauer elas...

2003
Arun K. Pati Samuel L. Braunstein

It is known that if one could clone an arbitrary quantum state then one could send signals faster than the speed of light. Here, we show that deletion of an unknown quantum state for which two copies are available would also lead to superluminal signalling. However, the (Landauer) erasure of an unknown quantum state does not allow faster-than-light communication.  2003 Published by Elsevier B.V.

Journal: :Physical review letters 2004
Christophe Texier Gilles Montambaux

We study the quantum transport through networks of diffusive wires connected to reservoirs in the Landauer-Büttiker formalism. The elements of the conductance matrix are computed by the diagrammatic method. We recover the combination of classical resistances and obtain the weak localization corrections. For arbitrary networks, we show how the Cooperon must be properly weighted over the differen...

Journal: :Physical review letters 2004
T P Pareek

We present a generalized Landauer-Büttiker transport theory for multiterminal spin transport in the presence of spin-orbit interaction. Using this theory we point out that there exists equilibrium spin currents and nonequilibrium pure spin currents, without any magnetic element in the system. Quantitative results are presented for a Y-shaped conductor. It is shown that pure spin currents cause ...

2008
Peter Zahn Ingrid Mertig

Based on spin-density functional theory we calculate the electronic structure of a tunnel junction consisting of two magnetic Fe layers separated by an insulating vacuum barrier selfconsistently. For the conductance the Landauer formula is evaluated in the ballistic limit as function of the magnetic configuration. Based on these conductances the tunnel magnetoresistance (TMR) ratio is obtained....

2011
Thomas A. Davis Michael R. Landauer Steven R. Mog Michal Barshishat-Kupper Stephen R. Zins Mihret F. Amare Regina M. Day

or radiation sensitization in a murine model of total body irradiation Thomas A. Davis, Michael R. Landauer, Steven R. Mog, Michal Barshishat-Kupper, Stephen R. Zins, Mihret F. Amare, and Regina M. Day Department of Regenerative Medicine, Naval Medical Research Center, Silver Spring, Md., USA; Armed Forces Radiobiology Research Institute, Uniformed Services University of the Health Sciences, Be...

Journal: :Nano letters 2007
Adam W Bushmaker Vikram V Deshpande Marc W Bockrath Stephen B Cronin

Raman spectra of individual pristine suspended single-walled carbon nanotubes are observed under high electrical bias. The LO and TO modes of the G band behave differently with respect to voltage bias, indicating preferential electron-phonon coupling and nonequilibrium phonon populations, which cause negative differential conductance in suspended devices. By correlating the electron resistivity...

2000
Charles King Marshall Van Alstyne

Almost every major consulting firm offers a variation on IT benchmarking or knowledge management to help companies improve their resource use and gauge the efficacy of their IT investments. Despite the perceived importance that such ubiquitous offerings imply, general evidence for any productivity enhancements did not appear until 1996 (Brynjolfsson & Hitt). The continued absence of productivit...

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