scholarly journals Computer Simulation of the Electric Transport Properties of the FeSe Monolayer

2020 ◽  
Vol 57 (6) ◽  
pp. 3-11
Author(s):  
D. Sergeyev ◽  
N. Zhanturina ◽  
L. Myasnikova ◽  
A.I. Popov ◽  
A. Duisenova ◽  
...  

AbstractThe paper deals with the model research of electric transport characteristics of stressed and non-stressed FeSe monolayers. Transmission spectra, current-voltage characteristic (CVC) and differential conductivity spectra of two-dimensional FeSe nanostructure have been calculated within the framework of the density functional theory and non-equilibrium Green’s functions (DFT + NEGF). It has been shown that the electrophysical properties depend on the geometry of the sample, the substrate, and the lattice constant. On CVC of non-stressed sample in the range from −1.2 V to −1 and from 1.2 V to 1.4 V, a region of negative differential resistance (NDR) has been observed. NDR is at both signs of the applied voltage due to the symmetry of the nanostructure. d2I/dV2 is used to determine the nature of the electron-phonon interaction and the features of quasiparticle tunnelling in stressed and non-stressed samples. The results obtained can be useful for calculating new elements of 2D nanoelectronics.

2020 ◽  
Vol 90 (4) ◽  
pp. 598
Author(s):  
Д.М. Сергеев

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.


2015 ◽  
Vol 29 (20) ◽  
pp. 1550106 ◽  
Author(s):  
Xiaojiao Zhang ◽  
Keqiu Chen ◽  
Mengqiu Long ◽  
Jun He ◽  
Yongli Gao

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.


Author(s):  
I. Yu. Sklyadneva ◽  
Rolf Heid ◽  
Pedro Miguel Echenique ◽  
Evgueni Chulkov

Electron-phonon interaction in the Si(111)-supported rectangular √(7 ) ×√3 phases of In is investigated within the density-functional theory and linear-response. For both single-layer and double-layer √(7 ) ×√3 structures, it...


2018 ◽  
Vol 32 (29) ◽  
pp. 1850323
Author(s):  
Ting Ting Zhang ◽  
Cai Juan Xia ◽  
Bo Qun Zhang ◽  
Xiao Feng Lu ◽  
Yang Liu ◽  
...  

The electronic transport properties of oligo p-phenylenevinylene (OPV) molecule sandwiched with symmetrical or asymmetric tailoring graphene nanoribbons (GNRs) electrodes are investigated by nonequilibrium Green’s function in combination with density functional theory. The results show that different tailored GNRs electrodes can modulate the current–voltage characteristic of molecular devices. The rectifying behavior can be observed with respect to electrodes, and the maximum rectification ratio can reach to 14.2 in the asymmetric AC–ZZ GNRs and ZZ–AC–ZZ GNRs electrodes system. In addition, the obvious negative differential resistance can be observed in the symmetrical AC-ZZ GNRs system.


2011 ◽  
Vol 391-392 ◽  
pp. 1128-1131
Author(s):  
You Lin Peng ◽  
Yan Hong Zhou ◽  
Li Li Zhou

We perform first-principles calculation of the transport properties of alumium-phosphorus dopped Si atomic nanowire coupled to two Al(100) nanoscale electrodes using the non-equilibrium Green formalism combined with the density-functional theory. In particular, the alumium-phosphorus dopped silicon wire with seven atoms sandwiched between the Al(100) electrodes is considered. It is found that the transport properties are sensitive to the dopping position of the alumium and the phosphorus on the silicon wire. The equilibrium conductance of the pure silicon wire is rather big, close to 3 G0, Three eigenchannels which contribute to the equilibrium conductance are fully open. All cases of the alumium-phosphorus dopping reduce the conductivity of the pure silicon wire. In particular, the conductance of the wire decreases to 0.7 G0 when a phosphorus substitutes the third silicon atom and a alumium substitutes the sixed silicon atom. The current-voltage(I-V) curves of these cases vary dramatically. The current across the wire with a phosphorus substitutes the third silicon atom and a alumium substitutes the sixed silicon atom is rather smaller than the that across the pure silicon. A detailed analysis of the transmission coefficient of the eigenchannels, the projected density of states are made to reveal the mechanism of the differences.


2015 ◽  
Vol 14 (01) ◽  
pp. 1550005 ◽  
Author(s):  
Wen Liu ◽  
Jie Cheng ◽  
Jian-Hua Zhao ◽  
Cai-Juan Xia ◽  
De-Sheng Liu

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.


2014 ◽  
Vol 1070-1072 ◽  
pp. 479-482
Author(s):  
Li Hua Wang ◽  
Heng Fang Meng ◽  
Bing Jun Ding ◽  
Yong Guo

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).


2008 ◽  
Vol 07 (02n03) ◽  
pp. 95-102 ◽  
Author(s):  
M. D. GANJI ◽  
H. AGHAIE ◽  
M. R. GHOLAMI

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.


Author(s):  
Д.М. Сергеев ◽  
А.Г. Дуйсенова

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.


2019 ◽  
Vol 33 (19) ◽  
pp. 1950205
Author(s):  
Qinghua Zhou ◽  
Ziqing Wei ◽  
Wei Hu ◽  
Yan Liang ◽  
Wenhua Liu ◽  
...  

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.


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