scholarly journals Precise Control of Single-phenanthrene Junction’s Conductance

2021 ◽  
Author(s):  
Alaa Al-Jobory ◽  
Abdelkareem Al-Meshal ◽  
Zainelabideen Yousif Mijbil
Keyword(s):  
Nitrogen Atom ◽  
Quantum Interference ◽  
Molecular Devices ◽  
Pendant Group ◽  
Precise Control ◽  
Electronic Conductance ◽  
Molecular Conductance ◽  
Homo Lumo

Abstract The electronic transmission of fifteen potential configurations of single-phenanthrene junction has been theoretically investigated. The structures include para-para, para-meta, and meta-meta combined with phenyl pendant group and substituted nitrogen atom. The results show that the para-meta, which offers a tunable antiresonance in the HOMO-LUMO gap, is the most suitable for synthesizing nano-device. The antiresonance is susceptible (unsusceptible) to the heteromotif location at site four (five). Hence, our paper presents the appropriate hetero-motif conditions—type and location— to synthesize molecular devices with the desired electronic conductance. The study also deepen the understanding of the molecular conductance by demonstrating the active and inactive sites to create and tune antiresonances. It finally introduces the essential impact of connectivity, quantum interference, and aromaticity in controlling the conductance of single-phenanthrene junction.

The Quantum Length Dependence of Conductance in Molecular Device: An Ab Initio Study

2010 ◽  
Vol 663-665 ◽  
pp. 519-522
Author(s):  
Cai Juan Xia ◽  
Han Chen Liu ◽  
Ying Tang Zhang
Keyword(s):  
Electronic Transport ◽  
First Principles ◽  
Electronic Structures ◽  
Density Functional ◽  
Molecular Device ◽  
Functional Theory ◽  
Length Dependence ◽  
Molecular Conductance ◽  
Homo Lumo ◽  
Molecular Compounds

By Applying Nonequilibrium Green’s Function Formalism Combined First-Principles Density Functional Theory, we Investigate the Electronic Transport Properties of Thiophene and Furan Molecules with Different Quantum Length. the Influence of HOMO-LUMO Gaps and the Spatial Distributions of Molecular Orbitals on the Electronic Transport through the Molecular Device Are Discussed in Detail. the Results Show that the Transport Behaviors Are Determined by the Distinct Electronic Structures of the Molecular Compounds. the Length Dependence of Molecular Conductance Exhibits its Diversity for Different Molecules.

Substitution Pattern Controlled Charge Transport in BN-Embedded Aromatics-Based Single-Molecule Junctions

2021 ◽  
Author(s):  
Hongxiang Li ◽  
Rui Wang ◽  
Kai Song ◽  
Caiyun Wei ◽  
Wenjing Hong ◽  
...  
Keyword(s):  
Charge Transport ◽  
Single Molecule ◽  
Molecular Devices ◽  
Substitution Pattern ◽  
Single Molecule Level ◽  
Single Molecule Junctions ◽  
Molecular Conductance

The understanding of charge transport at single-molecule level is a pre-requisite for the fabrication of molecular devices. Here, we systematically investigate the relation among molecular conductance, substitution pattern and stimuli...

scholarly journals The Anomalous Effect of Quantum Interference in Organic Spin Filters

2020 ◽  
Author(s):  
Ashima Bajaj ◽  
Prabhleen Kaur ◽  
Aakanksha Sud ◽  
Marco Berritta ◽  
Md. Ehesan Ali
Keyword(s):  
Quantum Interference ◽  
Density Functional ◽  
Organic Radicals ◽  
Spin Coupling ◽  
Anomalous Effect ◽  
Spin Filters ◽  
Molecular Conductance ◽  
Spin Spin Coupling ◽  
Spin Filtering

The molecular topology in the single-molecular nano-junctions through which the de Broglie wave propagates plays a crucial role in controlling the molecular conductance. The enhancement and reduction of the conductance due to constructive and destructive Quantum Interference (QI) in para and meta connected molecules respectively has already been well established. Herein, we investigated the influence of QI on spin transport in the molecular junctions containing organic radicals as magnetic centres. The role of the localized spins on the QI as well as on spin filtering capability is investigated employing density functional theory in combination with non-equilibrium Green's function (NEGF-DFT) techniques. Various organic radicals including nitroxide (NO), phenoxy (PO) and methyl (CH2) radicals attached to the central benzene ring of pentacene with different terminal connections (para and meta) to gold electrodes are examined. Due to more obvious QI effects, para connected pentacene is found to be more conductive than meta one. Surprisingly, on incorporating a radical centre, along with spin filtering, a significant quenching of QI effects is observed which manifests itself in such a way that the conductance of meta coupled radicals is found to be more than para by two orders of magnitude. The decoherence induced by radical centre is analysed and discussed in terms of spin-spin coupling of radical's unpaired electron with the tunneling electrons.<br>

scholarly journals The Anomalous Effect of Quantum Interference in Organic Spin Filters

2020 ◽  
Author(s):  
Ashima Bajaj ◽  
Prabhleen Kaur ◽  
Aakanksha Sud ◽  
Marco Berritta ◽  
Md. Ehesan Ali
Keyword(s):  
Quantum Interference ◽  
Density Functional ◽  
Organic Radicals ◽  
Spin Coupling ◽  
Anomalous Effect ◽  
Spin Filters ◽  
Molecular Conductance ◽  
Spin Spin Coupling ◽  
Spin Filtering

The molecular topology in the single-molecular nano-junctions through which the de Broglie wave propagates plays a crucial role in controlling the molecular conductance. The enhancement and reduction of the conductance due to constructive and destructive Quantum Interference (QI) in para and meta connected molecules respectively has already been well established. Herein, we investigated the influence of QI on spin transport in the molecular junctions containing organic radicals as magnetic centres. The role of the localized spins on the QI as well as on spin filtering capability is investigated employing density functional theory in combination with non-equilibrium Green's function (NEGF-DFT) techniques. Various organic radicals including nitroxide (NO), phenoxy (PO) and methyl (CH2) radicals attached to the central benzene ring of pentacene with different terminal connections (para and meta) to gold electrodes are examined. Due to more obvious QI effects, para connected pentacene is found to be more conductive than meta one. Surprisingly, on incorporating a radical centre, along with spin filtering, a significant quenching of QI effects is observed which manifests itself in such a way that the conductance of meta coupled radicals is found to be more than para by two orders of magnitude. The decoherence induced by radical centre is analysed and discussed in terms of spin-spin coupling of radical's unpaired electron with the tunneling electrons.<br>

scholarly journals Quantum interference and heteroaromaticity of para- and meta-linked bridged biphenyl units in single molecular conductance measurements

2017 ◽  
Vol 7 (1) ◽  
Author(s):  
Markus Gantenbein ◽  
Lin Wang ◽  
Alaa A. Al-jobory ◽  
Ali K. Ismael ◽  
Colin J. Lambert ◽  
...  
Keyword(s):  
Quantum Interference ◽  
Molecular Conductance

scholarly journals Charge transfer versus molecular conductance: molecular orbital symmetry turns quantum interference rules upside down

2015 ◽  
Vol 6 (7) ◽  
pp. 4196-4206 ◽  
Author(s):  
Natalie Gorczak ◽  
Nicolas Renaud ◽  
Simge Tarkuç ◽  
Arjan J. Houtepen ◽  
Rienk Eelkema ◽  
...  
Keyword(s):  
Charge Transfer ◽  
Molecular Orbital ◽  
Quantum Interference ◽  
Interference Effects ◽  
Orbital Symmetry ◽  
Molecular Conductance

Molecular orbital symmetry considerations can strongly affect the nature of quantum interference effects in charge transfer..

scholarly journals The role of quantum interference in determining transport properties of molecular bridges

2004 ◽  
Vol 2 (3) ◽  
pp. 524-533 ◽  
Author(s):  
Kamil Walczak
Keyword(s):  
Quantum Interference ◽  
Molecular System ◽  
Tight Binding ◽  
Transmission Function ◽  
Molecular Devices ◽  
Binding Model ◽  
Quantum Interference Effect ◽  
Current Voltage ◽  
Essential Question

AbstractAn analytical approach to the electron transport phenomena in molecular devices is presented. The analyzed devices are composed of various molecular bridges attached to two semi-infinite electrodes. Molecular system is described within the tight-binding model, while the coupling to the electrodes is analyzed through the use of Newns-Anderson chemisorption theory. The current-voltage (I-V) characteristics are calculated through the integration of transmission function in the standard Landauer formulation. The essential question of quantum interference effect of electron waves is diseussed in three aspects: (i) the geometry of a molecular bridge, (ii) the presence of an external magnetic field and (iii) the location of chemical substituent.

scholarly journals Quantum Interference in Coherent Molecular Conductance

2009 ◽  
Vol 103 (26) ◽  
Author(s):  
Julián Rincón ◽  
K. Hallberg ◽  
A. A. Aligia ◽  
S. Ramasesha
Keyword(s):  
Quantum Interference ◽  
Molecular Conductance

scholarly journals Controlling Quantum Interference by Regulating Charge on the Bridging N Atom of Pyrrolodipyridine Molecular Junctions

2019 ◽  
Author(s):  
Saman Naghibi ◽  
Ali K. Ismael ◽  
Andrea Vezzoli ◽  
Mohsin K. Al-Khaykanee ◽  
Xijia Zheng ◽  
...  
Keyword(s):  
Quantum Interference ◽  
Molecular Wires ◽  
Molecular Junctions ◽  
Scanning Probe ◽  
Molecular Wire ◽  
Interference Effects ◽  
Electronic Density ◽  
Molecular Conductance

<b>Control of quantum interference features</b>: molecular junctions incorporating pyrrolodipyridine-based molecular wires were fabricated by scanning probe methods. Quantum interference effects were introduced by employing <i>meta</i>-connected molecules, and modulated in magnitude by changing the substituent on the pyrrolic N. Dramatic changes in molecular conductance and DFT transport calculations demonstrate the storng effect that small changes in electronic density can have on the overall conductance of a molecular wire.

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