Influence of spatial distribution of molecule on the switching behavior: A first-principles study

2018 ◽  
Vol 17 (06) ◽  
pp. 1850038 ◽  
Author(s):  
Jingjuan Yang ◽  
Xiaoxiao Han ◽  
Peipei Yuan ◽  
Baoan Bian ◽  
Bin Liao

We perform first-principles calculations to investigate the electronic transport properties of chalcone and flavanone molecules sandwiched between graphene electrodes. These two molecules can be reversibly converted between open and closed states induced by pH, and the significant switching behaviors are observed. The currents and switching ratios are influenced by rotating molecules around the [Formula: see text] axis, which are discussed by the transmission eigenstates, electrostatic potential distributions and transmission spectra. The observed negative differential resistance effect is explained in chalcone configuration. The results suggest that spatial distributions of molecules will influence the performance of devices, indicating a potential application in future molecular circuits.

2020 ◽  
Vol 15 (2) ◽  
pp. 269-275
Author(s):  
Wei-Chao Zhang ◽  
Wei-Feng Sun

The spin-resolved electronic transport behaviors of VSe2 nanoribbons are theoretically investigated to explore their applications in spintronic devices, employing by the first-principles calculations combined with nonequilibrium Green's function scheme. The band structure, current varying curves with bias voltage between nanoribbon terminal electrodes and electronic transmission spectra of two representative VSe2 nanoribbons along zigzag and armchair crystallographic orientations are calculated respectively. The evident negative differential resistance under the bias voltage of ∼0.6 V for the armchair orientation has been found, implying the significant crystal anisotropy of VSe2 monolayer. Meanwhile, both the VSe2 nanoribbon devices along zigzag and armchair directions represent favorable spin filtering effect, suggesting they are prospective candidates as a multifunction material in spintronic and digital applications.


2018 ◽  
Vol 32 (32) ◽  
pp. 1850395
Author(s):  
Baoan Bian ◽  
Jingjuan Yang ◽  
Xiaoxiao Han ◽  
Peipei Yuan ◽  
Yuqiang Ding

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.


RSC Advances ◽  
2017 ◽  
Vol 7 (41) ◽  
pp. 25244-25252 ◽  
Author(s):  
Xiaoteng Li ◽  
Dongqing Zou ◽  
Bin Cui ◽  
Changfeng Fang ◽  
Jingfen Zhao ◽  
...  

We investigate the effects of line defects (558-defect and 57-defect) and edge hydrogenation (mono-hydrogenation and di-hydrogenation) on magnetism and spin transport of zigzag silicene nanoribbons (ZSiNRs) by first-principles calculations.


2013 ◽  
Vol 27 (16) ◽  
pp. 1350121 ◽  
Author(s):  
YUNJIN YU ◽  
YAOYU LI ◽  
LANGHUI WAN ◽  
BIN WANG ◽  
YADONG WEI

The electronic transport properties of one benzene-1,4-dithiolate molecule coupled by two aluminum metal leads were investigated by using first-principles method. The influence of the coupling distance between the molecule and the electrodes on I–V curve was studied thoroughly. Our calculations showed that when the system is in the most stable configuration, where the system total energy is the lowest, and the electron transport is in off-resonant state. Starting from the most stable configuration, when we gradually increase the distance between the molecule and electrodes and so decreasing the coupling strength of the molecule and electrodes, the conductance, as well as the I–V curve, does not decrease immediately but increase quickly at first. Only when we separate the molecule and electrodes far enough, the current begins to drop quickly. The total scattering charge density was presented in order to understand this phenomenon. A one-level quantum dot model is used to explain it. Finally, negative differential resistance was observed and analyzed.


2010 ◽  
Vol 152-153 ◽  
pp. 931-934
Author(s):  
Cai Juan Xia ◽  
Han Chen Liu ◽  
Qiu Ping Wang

The electronic transport properties of pyrrole trimer sandwiched between two electrodes are investigated by using nonequilibrium Green’s function formalism combined first-principles density functional theory. Theoretical results show that the system manifests negative differential resistance (NDR) behavior. A detailed analysis of the origin of negative differential resistance has been given by observing the shift in transmission resonance peak across the bias window with varying bias voltage.


RSC Advances ◽  
2015 ◽  
Vol 5 (18) ◽  
pp. 13917-13922 ◽  
Author(s):  
Jian Shao ◽  
X. Y. Zhang ◽  
Yue Zheng ◽  
Biao Wang ◽  
Yun Chen

The transport properties of heterometallic n-alkanedithiol junctions were investigated via first-principles calculations.


2011 ◽  
Vol 25 (05) ◽  
pp. 699-710
Author(s):  
CAI-JUAN XIA ◽  
CHANG-FENG FANG ◽  
PENG ZHAO ◽  
DE-SHENG LIU

Based on nonequilibrium Green's function and first-principles calculations, we investigate the electronic transport properties of 4,4′-biphenyldithiol functionalized molecular junction with different torsion angles between two phenyl rings. Numerical results show that torsion angle plays an important role in the conducting behavior of molecular junction. By changing the torsion angle, molecule can exhibit a switching behavior. Especially, when the molecule is functionalized with NO 2 side group, it will perform a molecular memory effect. Furthermore, effects of different adsorption positions of sulfur atom on molecular memory are also discussed.


2013 ◽  
Vol 27 (17) ◽  
pp. 1350081 ◽  
Author(s):  
Y. MIN ◽  
J. H. FANG ◽  
C. G. ZHONG ◽  
Z. C. DONG ◽  
C. P. CHEN ◽  
...  

The first-principles calculations of the transport characteristics of 4-(5-(2-(5-(4-mercaptophenyl)thiophene-2-yl)ethyl)pyridin-2-yl)benzenethiol sandwiched between two gold leads are performed. The effect of rectification and negative differential resistance (NDR) are obtained, which promise the potential applications in the field of molecular electronics. The rectification effect is 4.49. The peak/valley ratio of the NDR effect is as large as 4.51 for the forward bias and 12.09 for the reverse bias. The strong coupling between gold lead and molecule through thiolate results in the localization of the energy states of gold lead, which may induce the effect of rectification and NDR.


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