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.

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.

First-Principles Study of Triangle Terarylene as a Possible Optical Molecular Switch

2011 ◽  
Vol 311-313 ◽  
pp. 526-529
Author(s):  
Cai Juan Xia ◽  
Han Chen Liu ◽  
Ji Xin Yin
Keyword(s):  
First Principles ◽  
Density Functional ◽  
Molecular Switch ◽  
Optical Switches ◽  
Functional Theory ◽  
Closed Ring ◽  
Potential Applications ◽  
Homo Lumo ◽  
Non Equilibrium Green’S Function ◽  
Theoretical Results

Using non-equilibrium Green’s function formalism combined with first-principles density functional theory, we investigate the electronic transport properties of a triangle terarylene(open- and closed-ring forms) optical molecular switch. The influence of the HOMO-LUMO gaps and the spatial distributions of molecular orbitals on the quantum transport through the molecular device is discussed. Theoretical results show that the conductance of the closed-ring is 3-8 times larger than that of open-ring, which expect that this system can be one of good candidates for optical switches due to this unique advantage, and may have some potential applications in future molecular circuit.

scholarly journals Electronic structure, transport, and collective effects in molecular layered systems

2017 ◽  
Vol 8 ◽  
pp. 2094-2105 ◽  
Author(s):  
Torsten Hahn ◽  
Tim Ludwig ◽  
Carsten Timm ◽  
Jens Kortus
Keyword(s):  
Master Equation ◽  
Density Functional ◽  
Copper Phthalocyanine ◽  
Pure Copper ◽  
Mean Field ◽  
Collective Effects ◽  
Functional Theory ◽  
Master Equation Approach ◽  
Device Applications ◽  
Non Equilibrium Green’S Function

The great potential of organic heterostructures for organic device applications is exemplified by the targeted engineering of the electronic properties of phthalocyanine-based systems. The transport properties of two different phthalocyanine systems, a pure copper phthalocyanine (CoPc) and a flourinated copper phthalocyanine–manganese phthalocyanine (F16CoPc/MnPc) heterostructure, are investigated by means of density functional theory (DFT) and the non-equilibrium Green’s function (NEGF) approach. Furthermore, a master-equation-based approach is used to include electronic correlations beyond the mean-field-type approximation of DFT. We describe the essential theoretical tools to obtain the parameters needed for the master equation from DFT results. Finally, an interacting molecular monolayer is considered within a master-equation approach.

Ab initio calculations of quantum transport of Au–GaN–Au nanoscale junctions

RSC Advances ◽  
2014 ◽  
Vol 4 (94) ◽  
pp. 51838-51844 ◽  
Author(s):  
Tian Zhang ◽  
Yan Cheng ◽  
Xiang-Rong Chen
Keyword(s):  
Density Functional Theory ◽  
Ab Initio Calculations ◽  
Ab Initio ◽  
Transport Properties ◽  
Quantum Transport ◽  
Electronic Transport ◽  
Density Functional ◽  
Function Method ◽  
Functional Theory ◽  
Non Equilibrium Green’S Function

We investigate the contact geometry and electronic transport properties of a GaN pair sandwiched between Au electrodes by performing density functional theory plus the non-equilibrium Green's function method.

FIRST-PRINCIPLES STUDY ON PHOTOSWITCHING BEHAVIOR IN SINGLE MOLECULE JUNCTION

2018 ◽  
Vol 25 (03) ◽  
pp. 1850070 ◽  
Author(s):  
BAO-AN BIAN ◽  
YA-PENG ZHENG ◽  
PEI-PEI YUAN ◽  
BIN LIAO ◽  
YU-QIANG DING
Keyword(s):  
Single Molecule ◽  
First Principles ◽  
Density Functional ◽  
Molecular Switch ◽  
Functional Theory ◽  
Current Voltage ◽  
Molecule Junction ◽  
Single Molecule Junction ◽  
Close Form ◽  
Non Equilibrium Green’S Function

We carry out first-principles calculations based on density functional theory and non-equilibrium Green’s function to investigate the electronic transport properties of a diarylethene-based molecule sandwiched between two Au electrodes. This molecular switch can be reversed between open and close forms by using light stimulation. We analyze the switch behavior of these two forms through the current–voltage curves, transmission spectra and molecular projected self-consistent Hamiltonian. It has been found that the current of the close form is significantly larger than the open form, and there is a large and stable switch ratio in a wide bias window. This result indicates that this molecule can become one of the good candidates for optical molecular switch in the future.

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.

Rectification in zigzag graphene/BN nanoribbon heterojunction

2018 ◽  
Vol 32 (32) ◽  
pp. 1850395
Author(s):  
Baoan Bian ◽  
Jingjuan Yang ◽  
Xiaoxiao Han ◽  
Peipei Yuan ◽  
Yuqiang Ding
Keyword(s):  
Density Functional Theory ◽  
First Principles ◽  
Negative Differential Resistance ◽  
Density Functional ◽  
Differential Resistance ◽  
Transmission Spectra ◽  
Density Of State ◽  
Functional Theory ◽  
Negative Differential Resistance Effect ◽  
Non Equilibrium Green’S Function

We investigate the effect of changed BN nanoribbon on the rectifying behavior in zigzag graphene/BN nanoribbon heterojunction using first principles based on non-equilibrium Green’s function and density functional theory. The increased BN length in the scattering region reduces the rectifying performance of the device, and the maximum rectifying ratio is [Formula: see text] in the heterojunction. We discuss the different rectifying characteristics for the designed models by calculating the transmission spectra at different biases. The rectifying phenomenon is further investigated by the projected density of state of device. Furthermore, we explain the observed negative differential resistance effect by the transmission spectra and transmission eigenstates. The results suggest that the zigzag graphene/BN nanoribbon heterojunction leads to the asymmetric current, causing the rectifying phenomenon, and the BN length in the scattering region can modulate the rectifying performance of zigzag graphene/BN nanoribbon heterojunction.

scholarly journals Electronic and transport properties of zigzag phosphorene nanoribbons with nonmetallic atom terminations

RSC Advances ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 1400-1409 ◽  
Author(s):  
L. Sun ◽  
Z. H. Zhang ◽  
H. Wang ◽  
M. Li
Keyword(s):  
Density Functional Theory ◽  
Transport Properties ◽  
Electronic Properties ◽  
Green's Function ◽  
First Principles ◽  
Density Functional ◽  
Functional Theory ◽  
Non Equilibrium Green’S Function ◽  
Non Equilibrium ◽  
First Principles Method

Using the first-principles method based on density-functional theory and non-equilibrium Green's function, the electronic properties of zigzag ZPNRs terminated with NM atoms, as well as a pristine case, were studied systematically.

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