scholarly journals Investigation of quantum transport and local density of states in a graphene strip connected to a square lattice

2021 ◽  
Author(s):  
Elnaz Rostampour
Keyword(s):  
Quantum Transport ◽  
Dirac Point ◽  
Local Density ◽  
Square Lattice ◽  
Density Of State ◽  
Metallic Lead ◽  
Resonant Tunnelling ◽  
Quantum Billiard ◽  
Plasmon Polaritons ◽  
Theoretical Results

Abstract We theoretically express quantum transport at Dirac points via graphene quantum billiard as a non-magnetic material to connect metallic leads. Our results indicate that the quantum billiard of graphene is similar to a resonant tunnelling device. The centerpiece size and the Fermi energy of the graphene quantum billiard play an important role in the resonant tunnelling. In graphene, change of carrier density can affect plasmon polaritons. At the Dirac point, the conductivity of graphene depends on the geometry, so that the conduction of the evanescent modes is close to the theoretical value of 4e2/πh (where Planck's constant and the electron charge are denoted by h and e, respectively.). This transport property can be used to justify chaotic quantum systems and ballistic transistors. Our theoretical results demonstrate that the local density of state of the graphene sheet for EL = ER = 0 is larger than EL = ER = t (where EL (ER) is onsite energy of the left (right) metallic lead) unlike the current obtained from the calculations.

On the perturbation of a uniform tiling with resistors

2016 ◽  
Vol 30 (24) ◽  
pp. 1650166 ◽  
Author(s):  
M. Q. Owaidat ◽  
J. H. Asad ◽  
Zhi-Zhong Tan
Keyword(s):  
Green’S Function ◽  
Green's Function ◽  
Square Lattice ◽  
Resistor Network ◽  
Theoretical Results

The perturbation of a uniformly tiled resistor network by adding an edge (a resistor) to the network is considered. The two-point resistance on the perturbed tiling in terms of that on the perfect tiling is obtained using Green’s function. Some theoretical results are presented for an infinite modified square lattice. These results are confirmed experimentally by constructing an actual resistor lattice of size 13 × 13.

Electronic Structure and Mechanical Properties of Zircaloy-2 and Zircaloy-4: A First Principle Study

2013 ◽  
Author(s):  
Chunhai Lu ◽  
Wenkai Chen ◽  
Min Chen ◽  
Shijun Ni ◽  
Chengjiang Zhang
Keyword(s):  
Mechanical Properties ◽  
Electronic Structure ◽  
Zirconium Alloy ◽  
Local Density ◽  
Partial Density ◽  
Total Density ◽  
First Principle ◽  
Density Of State ◽  
Virtual Crystal Approximation ◽  
Anisotropic Mechanical Properties

The local-density approximation (LDA) coupled with the virtual crystal approximation (VCA) method electronic structure is applied to evaluate elastic constants, bulk modulus, shear modulus, Young’s modulus and Poisson’s ratio mechanic properties of metal zirconium, Zircaloy-2 and Zircaloy-4. The results show that there is no obvious difference in band structure and total density of state (DOS) between metal zirconium and zirconium alloy. However, p and d electron partial density of state (PDOS) presents the slight difference between metal zirconium and zirconium alloy. Zircaloy-2 and Zircaloy-4 present better elastic mechanical properties than metal zirconium. The metal zirconium and zirconium alloy show the anisotropic mechanical properties.

Structural, Phonon and Thermodynamic Properties of the Rocksalt Structure LiF from First Principles

2016 ◽  
Vol 850 ◽  
pp. 348-353 ◽  
Author(s):  
Hai Jun Hou ◽  
Hao Guan ◽  
Shun Ru Zhang ◽  
Lin Hua Xie ◽  
Lei Wang
Keyword(s):  
Thermodynamic Properties ◽  
Density Of States ◽  
Phonon Dispersion ◽  
Local Density ◽  
Wide Band ◽  
Present Calculation ◽  
Phonon Density ◽  
Phonon Density Of States ◽  
Rocksalt Structure ◽  
Theoretical Results

The structural, electronic, phonon and thermodynamic properties of rocksalt (RS) structure LiF are studied using a plane-wave pseudopotential method within the local density approximation (LDA). The values of lattice constants, elastic constants, and bulk modulus and its pressure derivatives are in well agreement with the available experimental data and other theoretical results. The LiF crystal exhibits a wide band gap of about 8.727 eV. The linear response method is applied to determine the phonon dispersion, phonon density of states and Born effective charge. The phonon frequencies at the Γ, X, L points are analyzed using group theory. We also calculate the thermodynamic functions such as free energy, enthalpy, entropy, specific heat using the phonon density of states. We compare the present calculation results satisfactorily to experimental and previous theoretical results.

Oxygen Bonding in Bismuth Layered Compounds SrBi2Ta2O9

2007 ◽  
Vol 997 ◽  
Author(s):  
Dong Su ◽  
Nan Jiang ◽  
Jianguo Wen ◽  
Jianshe Liu
Keyword(s):  
Scanning Transmission Electron Microscopy ◽  
Local Density ◽  
Layered Compounds ◽  
Density Approximation ◽  
Electron Loss ◽  
Density Of State ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
Fine Structures ◽  
Z Contrast

AbstractWith the help of the high resolution Z-contrast scanning transmission electron microscopy (STEM), the near edge fine structures of the electron loss spectroscopy (EELS) arises from different layers are investigated in SBT. The EELS spectra are interpreted by comparing with the calculation using linearnized augment plane wave (LAPW) method within the local density approximation (LDA). The oxygen bonding nature in different layers are discussed. In Bi2O2 layer, oxygen 2p state interacted with the Bi 6p state leads to a high t2g state in density of state while in SrTa2O7 layer, oxygen 2p state hybridized with Ta 5d and Sr 5d, which leads a higher eg state than t2g state.

Scanning tunneling spectroscopy of a magnetic adatom on graphene

2014 ◽  
Vol 28 (31) ◽  
pp. 1450225 ◽  
Author(s):  
Yang Gao ◽  
Kai-He Ding
Keyword(s):  
Gate Voltage ◽  
Local Density ◽  
Scanning Tunneling Spectroscopy ◽  
Tunneling Spectroscopy ◽  
Differential Conductance ◽  
Scanning Tunneling ◽  
Density Of State ◽  
Tunneling Microscopy ◽  
Substitutional Site ◽  
Kondo Resonance

We present a theoretic study on scanning tunneling spectroscopy (STS) of a magnetic adatom on graphene. Three typical configurations of adatoms on graphene are considered explicitly: the adatom is on the top of a carbon atom (TC), in a substitutional site (SC), or above the center of the honeycomb hexagon (HC). Based on the nonequilibrium Green's function method, we derive the local density of state (LDOS) for the adatom and the differential conductance through the scanning tunneling microscopy (STM) device. Our results show that in comparison with the cases of the TC and SC, there exists an anomalous broadening of the local adatom energy level in the HC, which pushes the adatom energy to first cross the Fermi level, leading to the appearance of an antiresonance in the LDOS due to the interference between the Kondo resonance and the broadened adatom level. Correspondingly, the bias dependence of the differential conductance in the HC exhibits a more asymmetric sharp Kondo peak pinned to the gate voltage, and its height still remains significantly large compared to that for the other two cases. Additionally, with decreasing the gate voltage, the Kondo peak in the differential conductance gradually decays, and eventually vanishes in the absence of the gate voltage.

scholarly journals Quantum transport at the Dirac point: Mapping out the minimum conductivity from pristine to disordered graphene

2015 ◽  
Vol 92 (20) ◽  
Author(s):  
Redwan N. Sajjad ◽  
Frank Tseng ◽  
K. M. Masum Habib ◽  
Avik W. Ghosh
Keyword(s):  
Quantum Transport ◽  
Dirac Point ◽  
Point Mapping

Dependence of Particle Number on Density of States of an Aluminum Nanocluster

2010 ◽  
Vol 3 (2) ◽  
pp. 88-94
Author(s):  
Natalya V. Tikhovskaya ◽  
Klimentiy N. Yugay
Keyword(s):  
Oxygen Atom ◽  
Hubbard Model ◽  
Density Of States ◽  
Lattice Site ◽  
Particle Number ◽  
Local Density ◽  
Aluminum Atom ◽  
Density Of State

On basis of the Hubbard model density of states of the 2D square nanosystem by size of N × N aluminum atoms with N = 3÷30, and also density of states of the 2D aluminum square nanocluster, where one of the aluminum atom is changed by oxygen atom, is calculated. It is shown that the local density of state depends on the total number of atoms in the cluster, and also on the location of atom in a lattice and the atom sort in a lattice site.

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