Effect of geometrical structure on transport properties of silicene nanoconstrictions*

We study electrical modulation of transport properties of silicene nanoconstrictions with different geometrical structures. We investigate the effects of the position and width of the central scattering region on the conductance with increasing Fermi energy. It is found that the conductance significantly depends on the position and the width of the nanoconstriction. Interestingly, the symmetrical structure of the central constriction region can induce a resonance effect and significantly increase the systemʼs conductance. We also propose a novel two-channel structure with an excellent performance on the conductance compared to the one-channel structure with the same total width. Such geometrically-induced conductance modulation of silicene nanostructures can be achieved in practice via current nanofabrication technology.

Download Full-text

Geometrical and Transport Properties of Disordered Fibre Networks: Analytical Results

Modern Physics Letters B ◽

10.1142/s0217984997001079 ◽

1997 ◽

Vol 11 (20) ◽

pp. 867-875 ◽

Cited By ~ 1

Author(s):

A. A. Rodríaguez ◽

E. Medina

Keyword(s):

Probability Distribution ◽

Transport Properties ◽

Geometrical Structure ◽

Mean Field ◽

Field Approximation ◽

Mean Field Approximation ◽

Fracture Networks ◽

Simplified Models ◽

Fibre Density ◽

Line Network

We study novel geometrical and transport properties of a 2D model of disordered fibre networks. To assess the geometrical structure we determine, analytically, the probability distribution for the number of fibre intersections and resulting segment sizes in the network as a function of fibre density and length. We also determine, numerically, the probability distribution of pore perimeters and areas. We find a non-monotonous behavior of the perimeter distribution whose main features can be explained by solving for two simplified models of the line network. Finally we formulate a mean field approximation to conduction, above the percolation threshold, using the derived results. Relevance of the results to fracture networks will be discussed.

Download Full-text

Paraelektrische Resonanz und dielektrische Dispersion von Wasser in Beryll-Einkristallen / Paraelectric Resonance and Dielectric Dispersion of Water in Beryl Single Crystals

Zeitschrift für Naturforschung A ◽

10.1515/zna-1974-1106 ◽

1974 ◽

Vol 29 (11) ◽

pp. 1558-1571

Author(s):

H.-J. Rehm

Keyword(s):

Electric Fields ◽

Resonance Effect ◽

Theoretical Description ◽

Tunnel Effect ◽

Zero Field ◽

Zero Field Splitting ◽

A Value ◽

Axis Parallel ◽

Electric Dipoles ◽

The One

Paraelectric resonance spectra of beryl crystals are observed in the X-band region between 5 and 20 kV/cm under the condition that the external electric field F[101̅0]. Additional dielectric measurements show, that the paraelectric centres are the monomeric water molecules in the beryl cavities. For water dipoles in beryl only two orientations of the molecular a-axis relative to the crystal C6-axis are possible, and only those with their a-axis parallel to the C6-axis contribute to the paraelectric resonance effect. The electric moment vector µ of these latter molecules may rotate in the (0001)-crystal plane, i. e. around their own a-axis, and has a value of (1.9 ± 0.2) D. A theoretical description of paraelectric resonance is presented for a simplified model: the electric dipoles have 6 equivalent equilibrium positions along the [101̅0]-directions, tunnel effect and external electric fields remove the site degeneracy and we observe a molecular Stark splitting. We calculate a value of (2.0 ± 0.4) GHz for the zero-field splitting in the one-parameter Hamiltonian model.

Download Full-text

Ballistic transport simulation of acceptor–donor C3N/C3B double-wall hetero-nanotube field effect transistors

Physical Chemistry Chemical Physics ◽

10.1039/c9cp03456k ◽

2019 ◽

Vol 21 (35) ◽

pp. 19567-19574 ◽

Cited By ~ 1

Author(s):

Jianwei Zhao ◽

Na Cheng ◽

Yuanyuan He

Keyword(s):

Field Effect ◽

Field Effect Transistors ◽

Ballistic Transport ◽

Channel Structure ◽

Potential Candidate ◽

Next Generation ◽

One Dimensional ◽

Transport Simulation ◽

The One ◽

Double Wall

The one-dimensional (1D) acceptor–donor (A–D) hetero-nanotube (HNT) has attracted much attention as a potential candidate for a channel structure of next-generation field effect transistors (FETs).

Download Full-text

Resistance-Capacitance Gas Sensor Based on Fractal Geometry

Chemosensors ◽

10.3390/chemosensors7030031 ◽

2019 ◽

Vol 7 (3) ◽

pp. 31 ◽

Cited By ~ 1

Author(s):

Taicong Yang ◽

Fengchun Tian ◽

James A. Covington ◽

Feng Xu ◽

Yi Xu ◽

...

Keyword(s):

Carbon Nanotubes ◽

Gas Sensor ◽

Fractal Geometry ◽

Geometrical Structure ◽

Gas Sensing ◽

Superior Performance ◽

Electrode Structure ◽

Geometrical Structures ◽

Surface Areas ◽

Sensor Resistance

An important component of any chemiresistive gas sensor is the way in which the resistance of the sensing film is interrogated. The geometrical structure of an electrode can enhance the performance of a gas-sensing device and in particular the performance of sensing films with large surface areas, such as carbon nanotubes. In this study, we investigated the influence of geometrical structure on the performance of gas sensors, combining the characteristics of carbon nanotubes with a novel gas sensor electrode structure based on fractal geometry. The fabricated sensors were tested with exposure to nitric oxide, measuring both the sensor resistance and capacitance (RC) of the sensor responses. Experimental results showed that the sensors with fractal electrode structures had a superior performance over sensors with traditional geometrical structures. Moreover, the RC characteristics of these fractal sensors could be further improved by using different test frequencies that could aid in the identification and quantification of a target gas.

Download Full-text

A Variational Solution of the Thermoelectric Transport Properties of Two-Component Nanocomposite Systems

MRS Proceedings ◽

10.1557/proc-793-s5.5 ◽

2003 ◽

Vol 793 ◽

Author(s):

Patrick L. Garrity ◽

Kevin L. Stokes

Keyword(s):

Transport Properties ◽

Conducting Polymer ◽

Quantum Confinement ◽

Three Dimensional ◽

Boltzmann Transport ◽

Thermoelectric Transport ◽

Two Component ◽

Thermoelectric Transport Properties ◽

Shell Particles ◽

The One

ABSTRACTThe successful fabrication of a nanocomposite in bulk form consisting of a randomly oriented assembly of nanoscale sized core-shell particles has required an increased understanding of the theoretical aspects of the thermoelectric transport properties. Our particular nanocomposite consists of a nanorod core in 1D quantum confinement coated with an outer conducting polymer shell. Upon fabrication of the bulk composite, these nanorods are embedded within a three-dimensional conducting polymer matrix. We address the nanorod thermoelectric components by assuming a single parabolic band within the one-dimension density of states. Both elastic and inelastic scattering of electrons or holes is accommodated by solving the variational form of the Boltzmann transport equation. An altered lattice thermal conductivity for the confined nanorods is calculated separately to account for boundary scattering that is important in low dimension structures. Exact expressions for the bulk effective electrical and thermal conductivities, Seebeck coefficient and figure of merit are then obtained through the field decoupling transformation, which is a special case of two-component composites. Our method is easily generalized to any two component composite of spherical or cylindrical microstructure and is independent of the materials bulk geometry. The results similarly apply to one, two or three dimensional transport regimes with or without quantum confinement merely by solving the appropriate fundamental transport equations for each constituent material. Comparison to experimental data is then presented which helps validate the nanocomposite theory.

Download Full-text

The Coherent Transport Properties of Electrons in a 4-Terminal Nano Device with Rashba Spin-Orbit Coupling in the Presence of Magnetic Field

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.496.175 ◽

2012 ◽

Vol 496 ◽

pp. 175-180

Author(s):

Hui Xian Wang ◽

Li Ben Li ◽

Da Wei Kang ◽

Hui Hui Liu

Keyword(s):

Magnetic Flux ◽

Transport Properties ◽

Coupling Strength ◽

Quantum Wires ◽

Channel Structure ◽

Spin Orbit Coupling ◽

Spin Orbit ◽

Coherent Transport ◽

Rashba Spin ◽

Magnetic Filed

We investigate the coherent transport properties of electrons in a side terminal of a four-terminal nano device made of quantum wires with Rashba spin-orbit (SO) coupling in the presence of magnetic filed. We numerically calculate the charge and spin conductances dependent on SO coupling strength and reduced flux. The results imply that the coherent transport in this device is determined by the interplay of Rashba SO coupling and magnetic filed. For specific values of magnetic flux and SO coupling strength, a complete blocking can take place. It also shows that there is a de-blocking phenomenon induced by the interplay of magnetic flux and SO coupling. Such a 4-terminal and multi-channel structure may provide more options of controlling methods for the coherent charge and spin transport.

Download Full-text