Numerical Analysis Of Carrier Statistics In Lowdimensional Nanostructure Devices

2012 ◽  
Author(s):  
Ismail Saad ◽  
M. Taghi Ahmadi ◽  
Munawar A. Riyadi ◽  
Razali Ismail ◽  
Vijay K. Arora
Keyword(s):  
Numerical Analysis ◽  
Key Words ◽  
Carrier Concentration ◽  
Fermi Energy ◽  
Density Of State ◽  
One Dimensional ◽  
Low Dimensional ◽  
De Broglie Wavelength ◽  
Strongly Degenerate ◽  
Degenerate Regime

Statistik pembawa bagi dimensi–bawah strukturnano adalah diperjelaskan. Ketumpatan kawasan (DOS) adalah bersamaan dengan λDd, di mana d ialah dimensi bagi strukturnano dan λD ialah gelombang De–Broglie bersamaan dengan kamiran Fermi–Dirac yang merangkumi statistik pembawa bagi semua tahap kemerosotan. Pada regim tak–merosot, hasil kajian menunjukkan pengreplikanan apa yang ditafsirkan dari statistic Boltzman. Akan tetapi, pada regim merosot hasilan adalah berubah–ubah. Hasilan bagi semua dimensi telah dianalisis secara berangka dan dibandingkan bagi kesemua tiga arah Cartesian. Dengan menggunakan DOS yang sepadan, kepekatan pembawa pada semua dimensi telah didapati berdasarkan statistik Fermi – Dirac. Tenaga Fermi yang berlandaskan hujung jalur adalah berfungsi kepada suhu yang tidak bergantung pada kepekatan pembawa pada regim tak–merosot. Di regim merosot yang tinggi, tenaga Fermi adalah berfungsi kepada kepekatan pembawa bersesuaian dengan dimensi tersebut tetapi tidak bergantung pada suhu. Kata kunci: Statistik pembawa; kepekatan pembawa; peranti satu–dimensi; pembawa merosot dan tak merosot The carrier statistics for low–dimensional nanostructure is elaborated. The density of state (DOS) is proportional to λDd where d is the dimensionality of the nanostructure and λD is the De–Broglie wavelength proportion of Fermi–Dirac (FD) integral that covers the carrier statistics to all degeneracy level. In the non-degenerate regime the results replicate what is expected from the Boltzmann statistics. However, the results vary in degenerate regime. The results for all dimensions are numerically analyzed and compared for all three Cartesian directions. With appropriate DOS, the carrier concentration in all dimensions is obtained based on the FD statistic. Fermi energy with respect to band edge is a function of temperature that is independent of the carrier concentration in the non–degenerate regime. In the strongly degenerate regime, the Fermi energy is a function of carrier concentration appropriate for given dimensionality, but is independent of temperature. Key words: Carrier statistics; carrier concentration; one dimensional devices; degenerate and nondegenerate carrier

scholarly journals Modelling of Graphene Nanoribbon Fermi Energy

2010 ◽  
Vol 2010 ◽  
pp. 1-6 ◽  
Author(s):  
Zaharah Johari ◽  
Mohammad Taghi Ahmadi ◽  
Desmond Chang Yih Chek ◽  
N. Aziziah Amin ◽  
Razali Ismail
Keyword(s):  
Band Structure ◽  
Carrier Concentration ◽  
Fermi Energy ◽  
Minimum Energy ◽  
Graphene Nanoribbon ◽  
Promising Alternative ◽  
Band Energy ◽  
One Dimensional ◽  
Statistic Study ◽  
Degenerate Regime

Graphene nanoribbon (GNR) is a promising alternative to carbon nanotube (CNT) to overcome the chirality challenge as a nanoscale device channel. Due to the one-dimensional behavior of plane GNR, the carrier statistic study is attractive. Research works have been done on carrier statistic study of GNR especially in the parabolic part of the band structure using Boltzmann approximation (nondegenerate regime). Based on the quantum confinement effect, we have improved the fundamental study in degenerate regime for both the parabolic and nonparabolic parts of GNR band energy. Our results demonstrate that the band energy of GNR near to the minimum band energy is parabolic. In this part of the band structure, the Fermi-Dirac integrals are sufficient for the carrier concentration study. The Fermi energy showed the temperature-dependent behavior similar to any other one-dimensional device in nondegenerate regime. However in the degenerate regime, the normalized Fermi energy with respect to the band edge is a function of carrier concentration. The numerical solution of Fermi-Dirac integrals for nonparabolic region, which is away from the minimum energy band structure of GNR, is also presented.

scholarly journals Carrier Statistics and Quantum Capacitance Models of Graphene Nanoscroll

2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
M. Khaledian ◽  
Razali Ismail ◽  
M. Saeidmanesh ◽  
M. T. Ahmadi ◽  
E. Akbari
Keyword(s):  
Temperature Effect ◽  
Electronic Properties ◽  
Carrier Concentration ◽  
Carrier Mobility ◽  
Analytical Approach ◽  
Structural Parameters ◽  
Quantum Capacitance ◽  
Density Of State ◽  
One Dimensional ◽  
Capacitance Model

As a new category of quasi-one-dimensional materials, graphene nanoscroll (GNS) has captivated the researchers recently because of its exceptional electronic properties like having large carrier mobility. In addition, it is admitted that the scrolled configurations for graphene indicate larger stability concerning the energy, as opposed to their counterpart planar configurations like nanoribbon, nanotube, and bilayer graphene. By utilizing a novel analytical approach, the current paper introduces modeling of the density of state (DOS), carrier concentration, and quantum capacitance for graphene nanoscroll (suggested schematic perfect scroll-like Archimedes spiral). The DOS model was derived at first, while it was later applied to compute the carrier concentration and quantum capacitance model. Furthermore, the carrier concentration and quantum capacitance were modeled for both degenerate and nondegenerate regimes, along with examining the effect of structural parameters and chirality number on the density of state and carrier concentration. Latterly, the temperature effect on the quantum capacitance was studied too.

Slope of consolidation lines

1985 ◽  
Vol 22 (2) ◽  
pp. 254-258 ◽  
Author(s):  
S. Chakrabarti ◽  
R. G. Horvath
Keyword(s):  
Key Words ◽  
One Dimensional ◽  
Isotropic Consolidation

Slopes of normal consolidation lines in one-dimensional and isotropic consolidation tests done on isotropically prepared samples of two soils are compared. It has been observed that the consolidation lines are not necessarily parallel. The ratios between the two slopes have been found to be 0.53 and 0.884 for kaolin and Dundas soil respectively. It is suggested that the value of this ratio may be dependent on the percentage and the type of clay in the soil. Key words: normally consolidated, one-dimensional, isotropic, Cc-line, λ-line.

scholarly journals Atomic-scale one-dimensional materials identified from graph theory

2021 ◽  
Author(s):  
Shunning Li ◽  
Zhefeng Chen ◽  
Zhi Wang ◽  
Mouyi Weng ◽  
Jianyuan Li ◽  
...  
Keyword(s):  
Graph Theory ◽  
Structural Information ◽  
Functional Materials ◽  
Atomic Scale ◽  
Computational Techniques ◽  
Electronic Band ◽  
One Dimensional ◽  
Atomic Chains ◽  
Future Data ◽  
Low Dimensional

Abstract The past decades have witnessed an exponential growth in the discovery of functional materials, benefited from our unprecedented capabilities in characterizing their structure, chemistry, and morphology with the aid of advanced imaging, spectroscopic and computational techniques. Among these materials, atomic-scale low-dimensional compounds, as represented by the two-dimensional (2D) atomic layers, one-dimensional (1D) atomic chains and zero-dimensional (0D) atomic clusters, have long captivated scientific interest due to their unique topological motifs and exceptional properties. Their tremendous potentials in various applications make it a pressing urgency to establish a complete database of their structural information, especially for the underexplored 1D species. Here we apply graph theory in combination with first-principles high-throughput calculations to identify atomic-scale 1D materials that can be conceptually isolated from their parent bulk crystals. In total, two hundred and fifty 1D atomic chains are shown to be potentially exfoliable. We demonstrate how the lone electron pairs on cations interact with the p-orbitals of anions and hence stabilize their edge sites. Data analysis of the 2D and 1D materials also reveals the dependence of electronic band gap on the cationic percolation network determined by graph theory. The library of 1D compounds systematically identified in this work will pave the way for the predictive discovery of material systems for quantum engineering, and can serve as a source of stimuli for future data-driven design and understanding of functional materials with reduced dimensionality.

scholarly journals A Simple Alternating Direction Method for the Conic Trust Region Subproblem

2018 ◽  
Vol 2018 ◽  
pp. 1-9
Author(s):  
Honglan Zhu ◽  
Qin Ni
Keyword(s):  
Trust Region ◽  
Alternating Direction Method ◽  
New Method ◽  
Quadratic Model ◽  
Descent Direction ◽  
Orthogonal Direction ◽  
Trust Region Subproblem ◽  
One Dimensional ◽  
Alternating Direction ◽  
Low Dimensional

A simple alternating direction method is used to solve the conic trust region subproblem of unconstrained optimization. By use of the new method, the subproblem is solved by two steps in a descent direction and its orthogonal direction, the original conic trust domain subproblem into a one-dimensional subproblem and a low-dimensional quadratic model subproblem, both of which are very easy to solve. Then the global convergence of the method under some reasonable conditions is established. Numerical experiment shows that the new method seems simple and effective.

The Chemical Bonding of Organic-Inorganic in Hybrid Compounds

2004 ◽  
Vol 848 ◽  
Author(s):  
Yadong Dai ◽  
Liling Guo ◽  
Minjie Hu ◽  
Kunyu Shi ◽  
Xinmin Min ◽  
...  
Keyword(s):  
Electronic Structure ◽  
Energy Density ◽  
Chemical Bonding ◽  
Fermi Energy ◽  
Energy Band Structure ◽  
Bond Orders ◽  
Density Of State ◽  
Hybrid Compound ◽  
Hybrid Compounds ◽  
Calculation Results

ABSTRACTAs has been discussed, research on the electronic structure between organic and inorganic atoms in hybrid compounds has become important. In our study, DV—Xα method was employed to calculate the electronic structure of the hybrid compound. The information obtained from the calculation included orbit charge, bonding order, Fermi energy, density of the state, etc. The influence of organic and inorganic parts on the energy band structure of the hybrid compound was discussed based on the calculation results of Fermi energy and density of state. The chemical bonding between organic and inorganic parts in the hybrid compound was also analyzed in detail according to the orbital charges and bond orders.

Numerical analysis of one-dimensional decay of a perched water table

1978 ◽  
Vol 36 (1-2) ◽  
pp. 109-119 ◽  
Author(s):  
K.K. Watson ◽  
F.D. Whisler ◽  
A.A. Curtis
Keyword(s):  
Numerical Analysis ◽  
Water Table ◽  
One Dimensional ◽  
Perched Water ◽  
Perched Water Table
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