نتایج جستجو برای: function negf formalism

تعداد نتایج: 1242621  

2005
HAROLD U. BARANGER Weitao Yang

for an Invited Paper for the MAR06 Meeting of The American Physical Society Conductance Through Single Organometallic Molecules1 HAROLD U. BARANGER, Duke University We have undertaken ab initio calculations of the conductance and I-V curve of a variety of single molecules bridging two metallic leads. The method adopted is a non-equilibrium Green function (NEGF) approach to transport combined wi...

In this article, a new structure is presented for MOS (Metal Oxide Semiconductor)-like junctionless carbon nanotube field effect transistor (MOS-like J-CNTFET), in which dual material gate with different work-functions are used. In the aforementioned structure, the size of the gates near the source and the drain are 14 and 6 nm, respectively, and the work-functions are equal and 0.5 eV less tha...

2014
Li Ming Loong Xuepeng Qiu Zhi Peng Neo Praveen Deorani Yang Wu Charanjit S. Bhatia Mark Saeys Hyunsoo Yang

While the effects of lattice mismatch-induced strain, mechanical strain, as well as the intrinsic strain of thin films are sometimes detrimental, resulting in mechanical deformation and failure, strain can also be usefully harnessed for applications such as data storage, transistors, solar cells, and strain gauges, among other things. Here, we demonstrate that quantum transport across magnetic ...

2015
Mischa Thesberg Mahdi Pourfath Neophytos Neophytou Hans Kosina

Thermoelectric materials can convert waste heat into usable power and thus have great potential as an energy technology. However, the thermoelectric efficiency of a material is quantified by its figure of merit, which has historically remained stubbornly low. One possible avenue towards increasing the figure of merit is through the use of low-dimensional nanograined materials. In such a system ...

Journal: :iranian journal of medical physics 0
reza faghihi school of mechanical engineering, nuclear engineering department, shiraz university, shiraz, iran radiation research center, shiraz university, shiraz, iran

introduction after the publication of task group number 43 dose calculation formalism by the american association of physicists in medicine (aapm), this method has been known as the most common dose calculation method in brachytherapy treatment planning. in this formalism, the water phantom is introduced as the reference dosimetry phantom, while the attenuation coefficient of the sources in the...

2009
A Mátyás T Kubis P Lugli C Jirauschek

We have applied two different simulation models for the stationary carrier transport and optical gain analysis in resonant phonon depopulation THz Quantum Cascade Lasers (QCLs), based on the semiclassical ensemble Monte Carlo (EMC) and fully quantum mechanical non-equilibrium Green’s functions (NEGF) method, respectively. We find in the incoherent regime near and above the threshold current a q...

2004
Tom G. Mackay Akhlesh Lakhtakia

The Bruggeman formalism provides an estimate of the effective permittivity of a particulate composite medium comprising two component mediums. The Bruggeman estimate is required to lie within the Wiener bounds and the Hashin–Shtrikman bounds. Considering the homogenization of weakly dissipative component mediums characterized by relative permittivities with real parts of opposite signs, we show...

2015
Yoshifumi Hyakutake

In this note, we construct Noether charges for the chiral supergravity, which contains the Lorentz Chern–Simons term, by applying Wald’s prescription to the vielbein formalism. We investigate the AdS3/CFT2 correspondence by using the vielbein formalism. The asymptotic symmetry group is carefully examined by taking into account the local Lorentz transformation, and we construct super Virasoro al...

2009
R. Stadler

We present density functional theory (DFT) based non-equilibrium Green’s function (NEGF) calculations for the conductance through a nitrobenzene molecule, which is anchored by pyridil-groups to Au electrodes. This work is building up on earlier theoretical studies where quantum interference effects have been identified both in qualitative tight-binding (TB) and in DFT descriptions for the same ...

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