ELECTRON TRANSPORT THROUGH MOLECULAR CHAINS

NANO ◽  
2007 ◽  
Vol 02 (02) ◽  
pp. 103-108 ◽  
Author(s):  
SANTANU K. MAITI
Keyword(s):  
Steady State ◽  
Electron Transport ◽  
Shot Noise ◽  
Coupling Strength ◽  
Tight Binding ◽  
Function Technique ◽  
Current Fluctuations ◽  
Tight Binding Model ◽  
Binding Model ◽  
Steady State Current

We study electron transport through molecular chains attached with two nonsuperconducting electrodes by the use of Green's function technique. Here, we do parametric calculations based on the tight-binding model to characterize the electron transport through such bridge systems and see that the transport properties are significantly affected by (a) the length of the molecular chain and (b) the molecule-to-electrode coupling strength. In this context, we also discuss the steady state current fluctuations, so-called shot noise, which is a consequence of the quantization of charge and is not directly available through conductance measurements.

scholarly journals Electron Transport Through Molecular Bridge Systems

2008 ◽  
Vol 8 (8) ◽  
pp. 4096-4100 ◽  
Author(s):  
Santanu K. Maiti
Keyword(s):  
Steady State ◽  
Electron Transport ◽  
Transport Properties ◽  
Shot Noise ◽  
Coupling Strength ◽  
Function Method ◽  
Tight Binding ◽  
Current Fluctuations ◽  
Steady State Current ◽  
Molecular Bridge

Electron transport characteristics are investigated through some molecular chains attached with two non-superconducting electrodes by the use of Green's function method. Here we do parametric calculations based on the tight-binding formulation to characterize the electron transport through such bridge systems. The transport properties are significantly influenced by (a) the length of the molecular chain and (b) the molecule-to-electrodes coupling strength and here we focus our results in these aspects. In this context we also discuss the steady state current fluctuations, so-called shot noise, which is a consequence of the quantization of charge and is not directly available through conductance measurements.

scholarly journals QUANTUM TRANSPORT THROUGH SINGLE PHENALENYL MOLECULE: EFFECT OF INTERFACE STRUCTURE

2007 ◽  
Vol 06 (06) ◽  
pp. 415-422 ◽  
Author(s):  
SANTANU K. MAITI
Keyword(s):  
Quantum Transport ◽  
Electronic Transport ◽  
Coupling Strength ◽  
Tight Binding ◽  
Interface Structure ◽  
Function Technique ◽  
Tight Binding Model ◽  
Parametric Approach ◽  
Binding Model ◽  
Molecular Bridge

The electronic transport characteristics through a single phenalenyl molecule sandwiched between two metallic electrodes are investigated by using Green's function technique. A parametric approach, based on the tight-binding model, is used to study the transport characteristics through such molecular bridge system. The electronic transport properties are significantly influenced by (a) the molecule-to-electrodes interface structure and (b) the molecule-to-electrodes coupling strength.

scholarly journals QUANTUM TRANSPORT THROUGH HETEROCYCLIC MOLECULES

2009 ◽  
Vol 23 (02) ◽  
pp. 177-187
Author(s):  
SANTANU K. MAITI ◽  
S. N. KARMAKAR
Keyword(s):  
Electron Transport ◽  
Transport Properties ◽  
Energy Levels ◽  
Tight Binding ◽  
Molecular Transport ◽  
Molecular Wires ◽  
Function Technique ◽  
Binding Model ◽  
Heterocyclic Molecules ◽  
Electron Transport Properties

We explore electron transport properties in molecular wires made of heterocyclic molecules (pyrrole, furan and thiophene) by using the Green's function technique. Parametric calculations are given based on the tight-binding model to describe the electron transport in these wires. It is observed that the transport properties are significantly influenced by (a) the heteroatoms in the heterocyclic molecules and (b) the molecule-to-electrodes coupling strength. Conductance (g) shows sharp resonance peaks associated with the molecular energy levels in the limit of weak molecular coupling, while they get broadened in the strong molecular coupling limit. These resonances get shifted with the change of the heteroatoms in these heterocyclic molecules. All the essential features of the electron transfer through these molecular wires become much more clearly visible from the study of our current-voltage (I-V) characteristics, and they provide several key information in the study of molecular transport.

Magnetic Spin Susceptibility of Graphene in Ferromagnetic State: A Tight-Binding Model Study

SPIN ◽  
2020 ◽  
Vol 10 (01) ◽  
pp. 2050004
Author(s):  
Sivabrata Sahu ◽  
G. C. Rout
Keyword(s):  
Coulomb Interaction ◽  
Tight Binding ◽  
High Energy ◽  
Spin Susceptibility ◽  
Function Technique ◽  
Tight Binding Model ◽  
Transfer Energy ◽  
Binding Model ◽  
Frequency Dependent ◽  
Model Study

We report here a tight-binding model study of frequency-dependent ferromagnetic spin susceptibility of the graphene system. The tight-binding Hamiltonian consists of electron hoppings up to third-nearest-neighbors, substrate and impurity effects in the presence of Coulomb interaction of electrons separately at two in-equivalent A and B sub-lattices of graphene. To calculate magnetic susceptibility, we calculate the two-particle electron Green’s functions by using Zubarev’s double time Green’s function technique. The electron occupations at A and B sub-lattices for both up and down spins are computed numerically and self-consistently. The frequency-dependent real part of ferromagnetic susceptibility of the system is computed numerically by taking [Formula: see text] grid points of the electron momentum. The susceptibility displays a sharp peak at the neutron momentum transfer energy at low energies and another higher energy resonance peak appearing at substrate-induced gap. The [Formula: see text]-peak shifts to a higher energy with the increase of momentum [Formula: see text]. The susceptibility shows that the high energy peak shifts to higher energies due to the corresponding increase of substrate-induced gap observed experimentally. It is observed that the Coulomb interaction suppresses the substrate-induced gap, but the impurity doping at A site enhances the substrate-induced gap, while doping at B site suppresses it.

scholarly journals ELECTRON TRANSPORT THROUGH MULTILEVEL QUANTUM DOT

2008 ◽  
Vol 07 (01) ◽  
pp. 51-61 ◽  
Author(s):  
SANTANU K. MAITI
Keyword(s):  
Electron Transport ◽  
Transport Properties ◽  
Energy Levels ◽  
Tight Binding ◽  
Current Amplitude ◽  
Function Technique ◽  
Noise Power ◽  
Disorder Strength ◽  
Binding Model ◽  
Surface Disorder

Quantum transport properties through some multilevel quantum dots sandwiched between two metallic contacts are investigated by the use of Green's function technique. Here, we do parametric calculations, based on the tight-binding model, to study the transport properties through such bridge systems. The electron transport properties are significantly influenced by (a) the number of quantized energy levels in the dots, (b) the dot-to-electrodes coupling strength, (c) the location of the equilibrium Fermi energy E F , and (d) the surface disorder. In the limit of weak-coupling, the conductance (g) shows sharp resonance peaks associated with the quantized energy levels in the dots, while, they get substantial broadening in the strong-coupling limit. The behavior of the electron transfer through these systems becomes much more clearly visible from our study of the current–voltage (I–V) characteristics. In this context, we also describe the noise power of current fluctuations (S) and determine the Fano factor (F) which provides an important information about the electron correlation among the charge carriers. Finally, we explore a novel transport phenomenon by studying the surface disorder effect in which the current amplitude increases with the increase of the surface disorder strength in the strong disorder regime, while, the amplitude decreases in the limit of weak disorder. Such an anomalous behavior is completely opposite to that of bulk disordered system where the current amplitude always decreases with the disorder strength. It is also observed that the current amplitude strongly depends on the system size which reveals the finite quantum size effect.

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