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.

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.

Gate-modulated electronic transport through a graphene nanoribbon composed of nanoribbons of different widths

2015 ◽  
Vol 14 (01) ◽  
pp. 1550005 ◽  
Author(s):  
Wen Liu ◽  
Jie Cheng ◽  
Jian-Hua Zhao ◽  
Cai-Juan Xia ◽  
De-Sheng Liu
Keyword(s):  
Integrated Circuits ◽  
Electronic Transport ◽  
Density Functional ◽  
Differential Resistance ◽  
Graphene Nanoribbon ◽  
Functional Theory ◽  
The Density Functional Theory ◽  
Effective Transport ◽  
Transport Channels ◽  
Non Equilibrium Green’S Function

Based on the non-equilibrium Green's function (NEGF) method combined with the density functional theory (DFT), we have studied the gate-modulated electronic properties of a graphene nanoribbon (GNR) which is composed of two GNRs of different widths. The results show that the charge transport is greatly modulated by the applied gate. Negative differential resistance (NDR) behaviors is found in such a system. With the increase in the gate, the NDR behaviors will disappear and reappear. Furthermore, under certain gate voltages multiple NDR behavior is found, the origin of which is attributed to the change of the number of effective transport channels and the variation of delocalization degree of the orbitals within the bias window. Interestingly, low bias NDR behavior is obtained which is desirable for integrated circuits from the point view of power consumption.

Modulation of Low Bias Negative Differential Resistance in a Molecular Device by Adjusting Anchoring Groups

2014 ◽  
Vol 1070-1072 ◽  
pp. 479-482
Author(s):  
Li Hua Wang ◽  
Heng Fang Meng ◽  
Bing Jun Ding ◽  
Yong Guo
Keyword(s):  
Electronic Transport ◽  
Negative Differential Resistance ◽  
Density Functional ◽  
Function Method ◽  
Differential Resistance ◽  
Carbon Chain ◽  
Molecular Device ◽  
Functional Theory ◽  
The Density Functional Theory ◽  
Anchoring Groups

We investigate electronic transport properties of molecular device models constructed by a dipyrimidinyl–dimethyl molecule embedding in a carbon chain, which are then coupled to the gold electrodes through thiol or isocyanide group. Using the density functional theory combined with the nonequilibrium Green’s function method, negative differential resistance behaviors are observed in such molecular junctions. Most importantly, system with the isocyanide group can achieve a larger negative differential resistance at lower bias voltage (0.1V).

Theory of the Rectifying Performance in Molecular Device: The Role of Anchoring Groups

2011 ◽  
Vol 181-182 ◽  
pp. 344-347 ◽  
Author(s):  
Cai Juan Xia ◽  
Han Chen Liu ◽  
Ying Tang Zhang
Keyword(s):  
Single Molecule ◽  
Electronic Transport ◽  
Density Functional ◽  
Electrical Response ◽  
Molecular Device ◽  
Functional Theory ◽  
Transmission Coefficients ◽  
External Bias ◽  
Anchoring Groups

The electronic transport of the single molecule via different anchoring groups is studied using density functional theory in conjunction with the nonequilibrium Green’s function. The results show that the electronic transport properties are strongly dependent on the anchoring groups. Asymmetric electrical response for opposite biases is observed resulting in significant rectification in current. The transmission coefficients and spatial distributions of molecular orbitals under various external biases voltage are analyzed, and it suggests that the asymmetry of the coupling between the molecule and the electrodes with external bias leads to rectifying performance.

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.

scholarly journals Об особенностях электронного транспорта в наноустройстве на основе молекулы, содержащей окислительно-восстановительный центр нитроамина

2020 ◽  
Vol 90 (4) ◽  
pp. 598
Author(s):  
Д.М. Сергеев
Keyword(s):  
Resonant Tunneling ◽  
Density Functional ◽  
Local Density ◽  
Differential Resistance ◽  
Functional Theory ◽  
Green Function Method ◽  
Voltage Range ◽  
Current Voltage ◽  
The Density Functional Theory ◽  
Nonequilibrium Green Function

Within the framework of the density functional theory in the local density approximation and the nonequilibrium Green function method (DFT + NEGF), electron transport was studied in a nanodevice consisting of a 2'-amino-4-ethynylphenyl-4'-ethynylphenyl-5'-nitro-1-benzenethiol molecule placed between gold electrodes. Current-voltage, dI/dV-characteristics, transmission spectrum and electron density of a nanodevice are calculated. It is shown that the current-voltage characteristic of the considered nanodevice in the voltage range of -0.8÷0.9 V acquires an N-shape and appears on it a section with negative differential resistance due to resonant tunneling of quasiparticles. The same changes are observed on the dI/dV-characteristic. The results obtained may be useful for calculating new promising electronic switching devices.

scholarly journals Электронный транспорт в модельных квазидвумерных ван-дер-ваальсовых наноустройствах

2021 ◽  
Vol 47 (8) ◽  
pp. 7
Author(s):  
Д.М. Сергеев ◽  
А.Г. Дуйсенова
Keyword(s):  
Molybdenum Disulfide ◽  
Electrical Transport ◽  
Density Functional ◽  
Local Density ◽  
Transmission Spectra ◽  
Current Voltage Characteristic ◽  
Functional Theory ◽  
Current Voltage ◽  
Positive Voltage ◽  
The Density Functional Theory

Within the framework of the density functional theory in the local density approximation and the method of nonequilibrium Green's functions, electron transport in a model nanodevice consisting of a combination of graphene, silicene, and molybdenum disulfide interconnected by van der Waals bonds is investigated. Current-voltage, dI / dV characteristics, and transmission spectra of nanodevices are calculated. It is revealed that the combination of silicene and molybdenum disulfide forms a new nanosystem with metallic properties, which are manifested in its electrical transport characteristics. It is shown that the graphene-MoS2-silicene hybrid nanostructure has rectifying properties due to the formation of a Schottky barrier, and steps of Coulomb origin appear on its current-voltage characteristic at a positive voltage.

Rectification and negative differential effects of Si2C2 clusters: An ab initio study

2019 ◽  
Vol 33 (19) ◽  
pp. 1950205
Author(s):  
Qinghua Zhou ◽  
Ziqing Wei ◽  
Wei Hu ◽  
Yan Liang ◽  
Wenhua Liu ◽  
...  
Keyword(s):  
Linear Form ◽  
Negative Differential Resistance ◽  
Density Functional ◽  
Differential Resistance ◽  
Molecular Devices ◽  
Ab Initio Study ◽  
Transmission Characteristics ◽  
Functional Theory ◽  
Transmission Properties ◽  
The Density Functional Theory

By combining the density functional theory (DFT) with the nonequilibrium Green’s function, we studied the transmission properties of Si2C2 clusters (the linear form M1 and the rhombic form M2). The result shows that the I-V characteristics of the cluster are closely related to the structure of the cluster. The change in the structure of the cluster causes a change in the coupling process between the cluster and the electrode, resulting in a change in its transmission characteristics. Compared with the linear form M1 system, the rhombic form M2 system has obvious rectification and negative differential resistance (NDR) effects, which makes it more advantageous as a candidate for molecular devices.

Spin polarization current induced by hydrogen hybrid within closed hexagon graphene nanoribbon devices

2016 ◽  
Vol 30 (27) ◽  
pp. 1650333 ◽  
Author(s):  
Yun Ren ◽  
Jun He ◽  
Zhi-Qiang Fan ◽  
Xiang Zhu ◽  
Yi Liu ◽  
...  
Keyword(s):  
Density Functional ◽  
Differential Resistance ◽  
Graphene Nanoribbon ◽  
Polarization Current ◽  
Functional Theory ◽  
Molecular Switching ◽  
The Density Functional Theory ◽  
Spin Polarized ◽  
Negative Differential Resistance Effect ◽  
Filtering Effect

We investigate the spin-polarized electronic transport properties of the closed hexagon graphene nanoribbon devices with different hydrogen hybrid of edge carbon atoms by using non-equilibrium Green’s functions in combination with the density functional theory. The results show that an excellent molecular switching with on/off ratio over 106, perfect spin-filtering effect and negative differential resistance effect have been observed. A detailed analysis has been presented.

Effect of length and negative differential resistance behavior in conjugated molecular wire tetrathiafulvalene devices

2015 ◽  
Vol 29 (20) ◽  
pp. 1550106 ◽  
Author(s):  
Xiaojiao Zhang ◽  
Keqiu Chen ◽  
Mengqiu Long ◽  
Jun He ◽  
Yongli Gao
Keyword(s):  
Electronic Transport ◽  
Negative Differential Resistance ◽  
Density Functional ◽  
Differential Resistance ◽  
Molecular Devices ◽  
Molecular Wire ◽  
Length Effect ◽  
Functional Theory ◽  
Current Voltage ◽  
The Density Functional Theory

The electronic transport properties of molecular devices constructed by conjugated molecular wire tetrathiafulvalene (TTF) have been studied by applying nonequilibrium Green’s functions in combination with the density-functional theory. Two molecular junctions with different wire lengths have been considered. The results show that the current–voltage curves of TTF devices can be modulated by the length of the molecular wire and negative differential resistance behaviors are observed in these systems. The mechanisms have been proposed for the length effect and negative differential resistance behavior.

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