ELECTRONIC TRANSPORT PROPERTIES OF TRANSITION METAL (Cu, Fe) PHTHALOCYANINES CONNECTING TO V-SHAPED ZIGZAG GRAPHENE NANORIBBONS

2014 ◽  
Vol 28 (08) ◽  
pp. 1450019 ◽  
Author(s):  
LILING CUI ◽  
BINGCHU YANG ◽  
XINMEI LI ◽  
JUN HE ◽  
MENGQIU LONG

Using nonequlilibrium Green's functions in combination with the density-functional theory, we investigate the spin transport properties of molecular junction based on metal ( Cu , Fe ) phthalocyanines between V-shaped zigzag-edged graphene nanorribons. The results show that the electronic transport properties mainly depend on the center transition metal. The negative differential resistance behaviors and spin splitting phenomenon can be observed.

2017 ◽  
Vol 16 (04) ◽  
pp. 1750032 ◽  
Author(s):  
Wen Liu ◽  
Fan-Hua Meng ◽  
Jian-Hua Zhao ◽  
Xiao-Hui Jiang

The electronic transport properties of hybrid nanoribbons constructed by substituting zigzag graphane nanoribbons (ZGaNRs) into zigzag graphene nanoribbons (ZGNRs) are investigated with the non-equilibrium Green’s function method and the density functional theory. Both symmetric and asymmetric ZGNRs are considered. The electronic transport of symmetric and asymmetric ZGNR-based hybrid nanoribbons behave distinctly differently from each other even in the presence of the same substitution positions of ZGaNRs. Moreover, the electronic transport of these hybrid systems is found to be enhanced or weakened compared with pristine ZGNRs depending on the substitution position and proportion. Our results suggest that such hybridization is an effective approach to modulate the transport properties of ZGNRs.


2019 ◽  
Vol 33 (29) ◽  
pp. 1950347 ◽  
Author(s):  
Xiao-Chong Liang ◽  
Xiao-Jiang Long ◽  
Lin Zhang ◽  
Jun Zhu

The structural and electronic transport properties of [Formula: see text] clusters are studied based on density functional theory (DFT). Their most stable structures are proved to be planar by the particle swarm optimization (PSO) algorithm, and have decreasing binding energies with the increasing number of Ga atom in clusters. The electronic transport properties of these clusters connected with two Al(1 0 0) electrodes are calculated by combining nonequilibrium Green’s-function (NEGF) with DFT. Most of them have an equilibrium conductance of above [Formula: see text], except for [Formula: see text]. Negative differential resistance (NDR) phenomenon of different level is observed in their I–V curves in bias ranges of from [Formula: see text] to [Formula: see text] V and from 0.7 to 1.1 V.


RSC Advances ◽  
2016 ◽  
Vol 6 (88) ◽  
pp. 84978-84984 ◽  
Author(s):  
Fang Xie ◽  
Zhi-Qiang Fan ◽  
Xiao-Jiao Zhang ◽  
Jian-Ping Liu ◽  
Hai-Yan Wang ◽  
...  

We investigate the electronic transport properties of a single cruciform diamine molecule connected to zigzag graphene nanoribbon electrodes by using the non-equilibrium Green's function formalism with density functional theory.


2018 ◽  
Vol 28 (3) ◽  
pp. 201 ◽  
Author(s):  
Tien Thanh Nguyen ◽  
Hoc Thai Bui ◽  
Ut Van Nguyen ◽  
Tuan Le

Influences of the symmetric Stone-Wales (SW) defect on the electronic transport properties of the zigzag graphene nanoribbons (ZGNRs) has been studied using $\it{ab}$ $\it{ initio}$ simulation based on density functional theory (DFT) combined with non-equilibrium Green's function (NEGF) technique. The calculated transmission spectra T(E) at various bias windows, device densities of states (DDOS), current characteristics as well as local density of states (LDOS) of the defective asymmetric and symmetric ZGNRs are presented in comparison of those for the pristine ZGNRs. It has been established the metallic character of the electronic transport in asymmetric ZGNRs, and in symmetric ones, the current has a semiconductor behavior, with negative differential resistance (NDR) effect. Symmetric SW defect, as a most unfavorable SW defect type for electric conductance, remarkably decreases the current values, but does not change the character of conductivity in both the asymmetric and symmetric ZGNRs. NDR has been explained by the altering by SW defect the number of frontier molecular orbitals entering bias windows.


2017 ◽  
Vol 31 (29) ◽  
pp. 1750222
Author(s):  
Jinfeng Song ◽  
Xiaojiang Long ◽  
Yanjun Hao ◽  
Jun Zhu ◽  
Yundong Guo

The structural and electronic transport properties of GaxNy ([Formula: see text]) clusters are investigated in the framework of density functional theory (DFT). To get their most stable structures, a strategy of particle swarm optimization (PSO) algorithm is adopted. It is found that the most stable cluster’s binding energy and HOMO–LUMO gap energy decrease with Ga atom’s number in cluster increasing. The electronic transport properties of the clusters connected with two Al(100) electrodes are obtained by a method of combining nonequilibrium Green’s function (NEGF) with DFT. Equilibrium conductance of all six-atom GaN cluster is low (less than 0.65 G0), and Ga2N4 has the highest one (0.635 G0). Significant negative differential resistance (NDR) phenomenon is observed in configurations with cluster Ga2N4, Ga3N3 and Ga5N1, and these three clusters have almost the same current value in voltage region from 0.8 V to 1.3 V.


2021 ◽  
Vol 16 (1) ◽  
Author(s):  
Yun Li ◽  
Xiaobo Li ◽  
Shidong Zhang ◽  
Liemao Cao ◽  
Fangping Ouyang ◽  
...  

AbstractStrain engineering has become one of the effective methods to tune the electronic structures of materials, which can be introduced into the molecular junction to induce some unique physical effects. The various γ-graphyne nanoribbons (γ-GYNRs) embedded between gold (Au) electrodes with strain controlling have been designed, involving the calculation of the spin-dependent transport properties by employing the density functional theory. Our calculated results exhibit that the presence of strain has a great effect on transport properties of molecular junctions, which can obviously enhance the coupling between the γ-GYNR and Au electrodes. We find that the current flowing through the strained nanojunction is larger than that of the unstrained one. What is more, the length and strained shape of the γ-GYNR serves as the important factors which affect the transport properties of molecular junctions. Simultaneously, the phenomenon of spin-splitting occurs after introducing strain into nanojunction, implying that strain engineering may be a new means to regulate the electron spin. Our work can provide theoretical basis for designing of high performance graphyne-based devices in the future.


Author(s):  
G. R. Berdiyorov ◽  
U. Khalilov ◽  
H. Hamoudi ◽  
Erik C. Neyts

AbstractUsing density functional theory in combination with the Green’s functional formalism, we study the effect of surface functionalization on the electronic transport properties of 1D carbon allotrope—carbyne. We found that both hydrogenation and fluorination result in structural changes and semiconducting to metallic transition. Consequently, the current in the functionalization systems increases significantly due to strong delocalization of electronic states along the carbon chain. We also study the electronic transport in partially hydrogenated carbyne and interface structures consisting of pristine and functionalized carbyne. In the latter case, current rectification is obtained in the system with rectification ratio up to 50%. These findings can be useful for developing carbyne-based structures with tunable electronic transport properties.


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.


2015 ◽  
Vol 1727 ◽  
Author(s):  
Yasutaka Nishida ◽  
Takashi Yoshida ◽  
Fumihiko Aiga ◽  
Yuichi Yamazaki ◽  
Hisao Miyazaki ◽  
...  

ABSTRACTIn this study, we investigated the influence of line defects consisting of pentagon-heptagon (5-7) pairs on the electronic transport properties of zigzag-edged and armchair-edged graphene nanoribbons (GNRs). Using the first-principles density functional theory, we study their electronic properties. To investigate their current-voltage (I-V) characteristics at low bias voltage (∼ 1 meV), we use the nonequilibrium Green’s function method. As a result, we found that the conductance of the GNRs having a connected line defect between source and drain shows better performance than that of the ideal zigzag-edged GNRs (ZGNRs). A detailed investigation of the transmission spectra and the wave function around the Fermi level reveals that the line defects arranged along the transport direction work similar to an edge state of the ZGNRs and can be an additional conduction channel. Our results suggest that such a line defect can be effective for low-resistance GNR interconnects.


Micromachines ◽  
2018 ◽  
Vol 10 (1) ◽  
pp. 26
Author(s):  
Baorui Huang ◽  
Fuchun Zhang ◽  
Yanning Yang ◽  
Zhiyong Zhang

The two-probe device of nanorod-coupled gold electrodes is constructed based on the triangular zinc oxide (ZnO) nanorod. The length-dependent electronic transport properties of the ZnO nanorod was studied by density functional theory (DFT) with the non-equilibrium Green’s function (NEGF). Our results show that the current of devices decreases with increasing length of the ZnO nanorod at the same bias voltage. Metal-like behavior for the short nanorod was observed under small bias voltage due to the interface state between gold and the ZnO nanorod. However, the influence of the interface on the device was negligible under the condition that the length of the ZnO nanorod increases. Moreover, the rectification behavior was observed for the longer ZnO nanorod, which was analyzed from the transmission spectra and molecular-projected self-consistent Hamiltonian (MPSH) states. Our results indicate that the ZnO nanorod would have potential applications in electronic-integrated devices.


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