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.

Charge Transfer Complexation Boosts Molecular Conductance Through Fermi Level Pinning

2018 ◽  
Author(s):  
Kun Wang ◽  
Andrea Vezzoli ◽  
Iain Grace ◽  
Maeve McLaughlin ◽  
Richard Nichols ◽  
...  
Keyword(s):  
Charge Transfer ◽  
Single Molecule ◽  
Quantum Interference ◽  
Transmission Function ◽  
Scanning Tunneling ◽  
Charge Transfer Complexes ◽  
Tunneling Microscopy ◽  
Quantum Interference Effect ◽  
Single Molecule Junctions ◽  
Charge Transfer Complexation

We have used scanning tunneling microscopy to create and study single molecule junctions with thioether-terminated oligothiophene molecules. We find that the conductance of these junctions increases upon formation of charge transfer complexes of the molecules with tetracyanoethene, and that the extent of the conductance increase is greater the longer is the oligothiophene, i.e. the lower is the conductance of the uncomplexed molecule in the junction. We use non-equilibrium Green's function transport calculations to explore the reasons for this theoretically, and find that new resonances appear in the transmission function, pinned close to the Fermi energy of the contacts, as a consequence of the charge transfer interaction. This is an example of a room temperature quantum interference effect, which in this case boosts junction conductance in contrast to earlier observations of QI that result in diminished conductance.<br>

scholarly journals Current Correlations in a Quantum Dot Ring: A Role of Quantum Interference

Entropy ◽  
2019 ◽  
Vol 21 (5) ◽  
pp. 527 ◽  
Author(s):  
Bogdan R. Bułka ◽  
Jakub Łuczak
Keyword(s):  
Correlation Functions ◽  
Quantum Interference ◽  
Cross Correlation ◽  
Destructive Interference ◽  
Quantum Interference Effect ◽  
Auto Correlation ◽  
Current Correlation ◽  
Relevant Role ◽  
Opposite Chirality

We present studies of the electron transport and circular currents induced by the bias voltage and the magnetic flux threading a ring of three quantum dots coupled with two electrodes. Quantum interference of electron waves passing through the states with opposite chirality plays a relevant role in transport, where one can observe Fano resonance with destructive interference. The quantum interference effect is quantitatively described by local bond currents and their correlation functions. Fluctuations of the transport current are characterized by the Lesovik formula for the shot noise, which is a composition of the bond current correlation functions. In the presence of circular currents, the cross-correlation of the bond currents can be very large, but it is negative and compensates for the large positive auto-correlation functions.

THEORETICAL INVESTIGATIONS OF QUANTUM TRANSPORT THROUGH CARBON NANOTUBE DEVICES

2000 ◽  
Vol 07 (05n06) ◽  
pp. 637-642 ◽  
Author(s):  
C. ROLAND ◽  
M. BUONGIORNO NARDELLI ◽  
H. GUO ◽  
H. MEHREZ ◽  
J. TAYLOR ◽  
...  
Keyword(s):  
Carbon Nanotube ◽  
Quantum Transport ◽  
Function Analysis ◽  
Tight Binding ◽  
Spin Valve ◽  
Superconducting Devices ◽  
Binding Model ◽  
Theoretical Investigations ◽  
Carbon Nanotube Devices

By combining a nonequilibrium Green's function analysis with a standard tight-binding model, we have investigated quantum transport through carbon nanotube devices. For finite-sized nanotubes, transport is dominated by resonant tunneling, with the conductance being strongly dependent on the length of the nanotubes. Turning to nanotube devices, we have investigated spin-coherent transport in ferromagnetic–nanotube–ferromagnetic devices and nanotube-superconducting devices. The former shows a significant spin valve effect, while the latter is dominated by resonant Andreev reflections. In addition, we discuss AC transport through carbon nanotubes and the role of photon-assisted tunneling.

Quantum interference effect in molecular system

2003 ◽  
pp. 487-488
Author(s):  
Jin Wang ◽  
H. M. Wiseman ◽  
Z. Ficek ◽  
G. J. Milburn
Keyword(s):  
Interference Effect ◽  
Quantum Interference ◽  
Molecular System ◽  
Quantum Interference Effect

Charge Transfer Complexation Boosts Molecular Conductance Through Fermi Level Pinning

2018 ◽  
Author(s):  
Kun Wang ◽  
Andrea Vezzoli ◽  
Iain Grace ◽  
Maeve McLaughlin ◽  
Richard Nichols ◽  
...  
Keyword(s):  
Charge Transfer ◽  
Single Molecule ◽  
Quantum Interference ◽  
Transmission Function ◽  
Scanning Tunneling ◽  
Charge Transfer Complexes ◽  
Tunneling Microscopy ◽  
Quantum Interference Effect ◽  
Single Molecule Junctions ◽  
Charge Transfer Complexation

We have used scanning tunneling microscopy to create and study single molecule junctions with thioether-terminated oligothiophene molecules. We find that the conductance of these junctions increases upon formation of charge transfer complexes of the molecules with tetracyanoethene, and that the extent of the conductance increase is greater the longer is the oligothiophene, i.e. the lower is the conductance of the uncomplexed molecule in the junction. We use non-equilibrium Green's function transport calculations to explore the reasons for this theoretically, and find that new resonances appear in the transmission function, pinned close to the Fermi energy of the contacts, as a consequence of the charge transfer interaction. This is an example of a room temperature quantum interference effect, which in this case boosts junction conductance in contrast to earlier observations of QI that result in diminished conductance.<br>

NANOSWITCH BASED ON NANOTUBES: BENT-NANOTUBES TRANSPORT

2004 ◽  
Vol 03 (01n02) ◽  
pp. 131-136 ◽  
Author(s):  
A. A. FARAJIAN ◽  
B. I. YAKOBSON ◽  
H. MIZUSEKI ◽  
Y. KAWAZOE
Keyword(s):  
Electronic Transport ◽  
Tight Binding ◽  
Mechanical Deformation ◽  
Localized States ◽  
Switching Behavior ◽  
Single Wall Carbon Nanotubes ◽  
Binding Model ◽  
Current Voltage ◽  
Potential Applications ◽  
Current Voltage Characteristics

The electronic transport through bent single-wall carbon nanotubes is studied. Using a four-orbital per atom tight-binding model, the relaxed configurations of a (10, 0) semiconducting nanotube at different bending angles are first obtained. The optimized structures are then used in calculating conductance and current–voltage characteristics of the systems. These results are used to establish a correspondence between the mechanical deformation and transport properties, with potential applications in, e.g., nanoswitches. The source of the switching behavior is explained in terms of the localized states within the bent region.

Sign in / Sign up

Export Citation Format

Share Document