First-principles quantum transport in S3 clusters

2014 ◽  
Vol 29 (02) ◽  
pp. 1450247
Author(s):  
Jing-Xin Yu ◽  
Xiu-Ying Liu ◽  
Li-Ying Zhang ◽  
Yan Cheng ◽  
Xiang-Rong Chen
Keyword(s):  
Bias Voltage ◽  
Quantum Transport ◽  
First Principles ◽  
Electrical Transport ◽  
Density Functional ◽  
Electrical Transport Properties ◽  
Open Chain ◽  
Functional Theory ◽  
External Bias ◽  
The Relationship

The quantum transport in S3 clusters sandwiched between Au electrodes was investigated using density functional theory and nonequilibrium Green's function method. Five different configurations were considered, and the equilibrium conductance and the projected density of states were obtained at optimal positions. Results revealed local minima for two strain chains connected to the pyramidal electrodes at the top site and a triangular S3 open chain linked to the pyramidal electrodes at the top hollow site. The relationship between conductance and external bias voltage was also calculated. Transmission of straight chains was determined by resonance and strongly affected by the bias voltage. Transport of top-hollow configuration was dominated by several closely spaced and broad molecular orbitals; hence, the transmission coefficient was almost flat around the gold Fermi level. The calculations proved that the coupling morphologies of S3 clusters connected with the electrodes significantly affected the electrical transport properties of nanoscale junctions.

Effect of the vacancy on the electrical transport properties of boron nitride nanosheets

2021 ◽  
Author(s):  
Reza Sadeghi ◽  
Mojtaba Yaghobi ◽  
Mohammad Reza Niazian ◽  
Mohammad ali Ramzanpour
Keyword(s):  
Electrical Transport ◽  
Density Functional ◽  
Vacancy Defect ◽  
Defect Engineering ◽  
Electrical Transport Properties ◽  
Functional Theory ◽  
Crystalline Materials ◽  
The Density Functional Theory ◽  
Left And Right ◽  
Non Equilibrium Green’S Function

Abstract Vacancies occur naturally in all crystalline materials. A vacancy is a point defect in a crystal in which an atom is removed at one of the lattice sites. The defect could be imported during the synthesis of the material or be added by defect engineering. In this paper by employing the density functional theory as well as the non-equilibrium Green’s function approach, the structure and electronic properties of the perfect and defected BN nanosheet would be obtained and compared. Besides, the influence of the vacancy defect position is evaluated. For this purpose, the defect is considered at the center, left, and right hand sides of the nanosheet. It is seen that the electric current changes by changing the position of the vacancy defect, which is related to the electronic structures of BN nanosheets. In addition, the transmission and conductance for BN nanosheets with vacancy continuously change by changing the bias voltage. The obtained results can benefit the design and implementation of BN nanosheets in nanoelectronic systems and devices.

scholarly journals Effect of Defects on Spontaneous Polarization in Pure and Doped LiNbO3: First-Principles Calculations

Materials ◽  
2018 ◽  
Vol 12 (1) ◽  
pp. 100 ◽  
Author(s):  
Weiwei Wang ◽  
Dahuai Zheng ◽  
Mengyuan Hu ◽  
Shahzad Saeed ◽  
Hongde Liu ◽  
...  
Keyword(s):  
Spontaneous Polarization ◽  
First Principles ◽  
Density Functional ◽  
Lattice Distortion ◽  
Stable Structure ◽  
First Principles Calculations ◽  
Functional Theory ◽  
The Density Functional Theory ◽  
Specific Configuration ◽  
The Relationship

Numerous studies have indicated that intrinsic defects in lithium niobate (LN) dominate its physical properties. In an Nb-rich environment, the structure that consists of a niobium anti-site with four lithium vacancies is considered the most stable structure. Based on the density functional theory (DFT), the specific configuration of the four lithium vacancies of LN were explored. The results indicated the most stable structure consisted of two lithium vacancies as the first neighbors and the other two as the second nearest neighbors of Nb anti-site in pure LN, and a similar stable structure was found in the doped LN. We found that the defects dipole moment has no direct contribution to the crystal polarization. Spontaneous polarization is more likely due to the lattice distortion of the crystal. This was verified in the defects structure of Mg2+, Sc3+, and Zr4+ doped LN. The conclusion provides a new understanding about the relationship between defect clusters and crystal polarization.

scholarly journals First-principles study of organic molecule for corrosion inhibition

2019 ◽  
Vol 116 ◽  
pp. 00007
Author(s):  
Rachid Belkada ◽  
Dalila Hammoutène ◽  
Rahma Tibigui ◽  
Ikram Hadj-Said
Keyword(s):  
First Principles ◽  
Global Economy ◽  
Density Functional ◽  
Corrosion Inhibitors ◽  
Computational Techniques ◽  
Corrosion Properties ◽  
Functional Theory ◽  
Fundamental Level ◽  
Organic Inhibitors ◽  
The Relationship

The widespread use of steel in various industries, especially in the transportation of hydrocarbons and gas, has recently gained a potential interest to explore eco-friendly solutions against corrosion. In fact, the highly aggressive environment generates considerable losses that affect global economy of countries that are mainly depending on the production and transport of energy. In the field of corrosion inhibitors, most common method so far available for protection against corrosion relies on synthetic one. These are unfortunately harmful to the environment as well to the human health, however they remain the most popular and the most effective due to their cost, and their ease of application. One of the most challenging issues in this area is the accurate understanding and measure of the degree of the passivation of corrosion inhibitors, which is complex and depend on many factors such as the nature of the metal, the fluid, the electronic structure of the inhibitor, the temperature, the exposure time, and so on. Recently, organic inhibitors have become increasingly attractive due to their competitive character as compared to the synthetic ones. With the use of advanced computational techniques enhanced by the development of density functional theory (DFT), it becomes possible to identify and design at the fundamental level, novel corrosion inhibitor molecules as complementary well established tool beside to the experimental techniques, which are often very expensive and time-consuming. In this work, we explore by mean of DFT, the anti-corrosion effect of the Lawsone molecule (2-hydroxy-1,4-naphthoquinone) and some of its derivatives to clarify and understand the relationship at the fundamental level between the anti-corrosion properties and the structure of the molecule in contact with the iron.

The image charge effect and vibron-assisted processes in Coulomb blockade transport: a first principles approach

Nanoscale ◽  
2015 ◽  
Vol 7 (45) ◽  
pp. 19231-19240 ◽  
Author(s):  
A. M. Souza ◽  
I. Rungger ◽  
U. Schwingenschlögl ◽  
S. Sanvito
Keyword(s):  
Quantum Transport ◽  
First Principles ◽  
Coulomb Blockade ◽  
Density Functional ◽  
Image Charge ◽  
Functional Theory ◽  
Master Equation Approach ◽  
Image Charge Effect ◽  
Coulomb Blockade Regime ◽  
Non Equilibrium Green’S Function

We present a combination of density functional theory and of both non-equilibrium Green's function formalism and a Master equation approach to accurately describe quantum transport in molecular junctions in the Coulomb blockade regime.

THEORETICAL STUDY OF THE ELECTRON TRANSPORT THROUGH THE CYSTEINE AMINO ACID NANOMOLECULAR WIRE

2008 ◽  
Vol 07 (02n03) ◽  
pp. 95-102 ◽  
Author(s):  
M. D. GANJI ◽  
H. AGHAIE ◽  
M. R. GHOLAMI
Keyword(s):  
Electrical Transport ◽  
Density Functional ◽  
Differential Resistance ◽  
Self Assembled Monolayer ◽  
Functional Theory ◽  
Transmission Coefficients ◽  
External Bias ◽  
The Density Functional Theory ◽  
Au Nanowires ◽  
Cysteine Amino Acid

In this paper, we study the electrical transport and Negative Differential Resistance (NDR) in a single molecular conductor consisting of a cysteine sandwiched between two Au (111) electrodes via the Density Functional Theory-based Nonequilibrium Green's Function (DFT-NEGF) method. We show that (surprisingly, despite their apparent simplicity, these Au /cysteine/ Au nanowires are shown to be a convenient NDR device) the smallest two-terminal molecular wire can exhibit NDR behavior to date. Experiments with a conventional or novel self-assembled monolayer (SAM) are proposed to test these predictions. The projected density of states (PDOSs) and transmission coefficients T(E) under various external voltage biases are analyzed, and it suggests that the variation of the coupling between the molecule and the electrodes with external bias leads to NDR.

scholarly journals Ab initio quantum transport in AB-stacked bilayer penta-silicene using atomic orbitals

RSC Advances ◽  
2018 ◽  
Vol 8 (59) ◽  
pp. 34041-34046 ◽  
Author(s):  
Eleni Chatzikyriakou ◽  
Padeleimon Karafiloglou ◽  
Joseph Kioseoglou
Keyword(s):  
Density Functional Theory ◽  
Quantum Transport ◽  
Current Density ◽  
First Principles ◽  
Density Functional ◽  
Free Standing ◽  
Functional Theory ◽  
Wannier Functions ◽  
Atomic Orbitals ◽  
Scattering Matrices

A methodology for parameter-free calculations of current density from first-principles using density functional theory, Wannier functions and scattering matrices is presented. The methodology is used on free-standing AB-stacked bilayer penta-silicene.

First-Principles and Quantum Transport Studies of Metal-Graphene End Contacts

2010 ◽  
Vol 1259 ◽  
Author(s):  
Kyeongjae Cho ◽  
Cheng Gong ◽  
Geunsik Lee ◽  
Weichao Wang ◽  
Bin Shan ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Quantum Transport ◽  
First Principles ◽  
Density Functional ◽  
Chemical Potential ◽  
Contact Structures ◽  
First Principles Calculations ◽  
Functional Theory ◽  
Transport Studies ◽  
Non Equilibrium Green’S Function

AbstractMetal-graphene contact is of critical significance in graphene-based nanoelectronics. There are two possible metal-graphene contact geometries: side-contact and end-contact. In this paper, we apply first-principles calculations to study metal-graphene end-contact for these three commonly used electrode metals (Ni, Pd and Ti) and find that they have distinctive stable end-contact geometries with graphene. Transport properties of these metal-graphene-metal (M-G-M) end-contact structures are investigated by density functional theory non-equilibrium Green’s function (DFT-NEGF) algorithm. The Transmission as a function of chemical potential (E-EF) shows asymmetric curves relative to the Fermi level. Transmission curves of Ni-G-Ni and Ti-G-Ti contact structures indicate that bulk graphene sheet is n-doped by Ni and Ti electrodes, but that of Pd-G-Pd shows p-doping of graphene by Pd electrode. The contact behaviors of these electrodes are consistent with experimental observations.

Effects of Oxygen Adsorption on Work Functions of Mo(110) Surface and Substrate

2010 ◽  
Vol 154-155 ◽  
pp. 832-839 ◽  
Author(s):  
Xu Huang ◽  
Zhen Zhen Weng ◽  
Gui Gui Xu ◽  
Zhi Gao Chen ◽  
Zhi Gao Huang
Keyword(s):  
First Principles ◽  
Density Functional ◽  
Oxygen Adsorption ◽  
Functional Theory ◽  
Oxygen Coverage ◽  
Probable Site ◽  
Density Surface ◽  
Work Functions ◽  
Adsorption Energies ◽  
The Relationship

Effects of oxygen atom adsorption on work functions of Mo(110) surface and substrate are investigated using first-principles methods based on density functional theory. The calculated results reveal that there exist a most probable site (named f1 site) in the surface oxygen adsorption on Mo(110) surface. Moreover, it is found that work functions of oxygen-adsorbed Mo(110) increase with increasing oxygen coverage, while the adsorption energies of oxygen decrease with increasing oxygen coverage. For a given oxygen coverage such as 0.333ML with surface f1 site, the work functions are insensitive to the distribution of oxygen atoms. In the meantime, the relationship among charge density, surface dipole density and the work function are discussed.

First-Principles Evaluation of the Potential of Borophene as a Monolayer Transparent Conductor

2017 ◽  
Author(s):  
Lyudmyla Adamska ◽  
Sridhar Sadasivam ◽  
Jonathan J. Foley ◽  
Pierre Darancet ◽  
Sahar Sharifzadeh
Keyword(s):  
First Principles ◽  
Density Functional ◽  
State Of The Art ◽  
Transparent Electrode ◽  
Visible Range ◽  
Two Dimensional ◽  
Transparent Conductor ◽  
Many Body ◽  
Functional Theory ◽  
Many Body Perturbation Theory

Two-dimensional boron is promising as a tunable monolayer metal for nano-optoelectronics. We study the optoelectronic properties of two likely allotropes of two-dimensional boron using first-principles density functional theory and many-body perturbation theory. We find that both systems are anisotropic metals, with strong energy- and thickness-dependent optical transparency and a weak (<1%) absorbance in the visible range. Additionally, using state-of-the-art methods for the description of the electron-phonon and electron-electron interactions, we show that the electrical conductivity is limited by electron-phonon interactions. Our results indicate that both structures are suitable as a transparent electrode.

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