scholarly journals Theoretical Analysis of the Faraday Effect in Carbon Nanotubes with Arbitrary Chirality

2013 ◽  
Vol 2013 ◽  
pp. 1-8
Author(s):  
Abbas Zarifi
Keyword(s):  
Magnetic Field ◽  
Carbon Nanotubes ◽  
Faraday Effect ◽  
Axial Magnetic Field ◽  
Tight Binding ◽  
Nearest Neighbour ◽  
Matrix Elements ◽  
Binding Model ◽  
Weak Magnetic Fields ◽  
Close Form

Using tight-binding model with nearest neighbour interactions, the optical properties of carbon nanotubes under the influence of an external magnetic field are analyzed. First, dipole matrix elements for two cases of light polarized parallel as well as perpendicular to the nanotube axis are analyzed. A close form analytic expression for dipole matrix is obtained for carbon nanotubes with arbitrary chirality in the case of light polarized parallel to the nanotube axis. Then the diagonal and off-diagonal elements of the frequency-dependent susceptibility in the presence of an axial magnetic field are investigated. The off-diagonal elements are applied to calculate the interband Faraday rotation and the Verdet constant. These effects should be clearly detectable under realistic conditions using weak magnetic fields.

TIGHT-BINDING MODEL FOR THE QUANTUM LADDER IN A MAGNETIC FIELD

1996 ◽  
Vol 10 (28) ◽  
pp. 3827-3856 ◽  
Author(s):  
KAZUMOTO IGUCHI
Keyword(s):  
Magnetic Field ◽  
Magnetic Flux ◽  
Ground State Energy ◽  
Ground State ◽  
State Energy ◽  
Tight Binding ◽  
Critical Value ◽  
Tight Binding Model ◽  
Binding Model ◽  
First Case

A tight-binding model is formulated for the calculation of the electronic structure and the ground state energy of the quantum ladder under a magnetic field, where the magnetic flux at the nth plaquette is given by ϕn. First, the theory is applied to obtain the electronic spectra of the quantum ladder models with particular magnetic fluxes such as uniform magnetic fluxes, ϕn=0 and 1/2, and the staggered magnetic flux, ϕn= (−1)n+1ϕ0. From these, it is found that as the effect of electron hopping between two chains—the anisotropy parameter r=ty/tx—is increased, there are a metal-semimetal transition at r=0 and a semimetal–semiconductor transition at r=2 in the first case, and metal-semiconductor transitions at r=0 in the second and third cases. These transitions are thought of as a new category of metal-insulator transition due to the hopping anisotropy of the system. Second, using the spectrum, the ground state energy is calculated in terms of the parameter r. It is found that the ground state energy in the first case diverges as r becomes arbitrarily large, while that in the second and third cases can have the single or double well structure with respect to r, where the system is stable at some critical value of r=rc and the transition between the single and double well structures is associated with whether tx is less than a critical value of txc. The latter cases are very reminiscent of physics in polyacetylene studied by Su, Schrieffer and Heeger.

scholarly journals Robust topological phase in proximitized core–shell nanowires coupled to multiple superconductors

2018 ◽  
Vol 9 ◽  
pp. 1512-1526 ◽  
Author(s):  
Tudor D Stanescu ◽  
Anna Sitek ◽  
Andrei Manolescu
Keyword(s):  
Magnetic Field ◽  
Longitudinal Magnetic Field ◽  
Tight Binding ◽  
Core Shell ◽  
Topological Phase ◽  
Binding Model ◽  
Chemical Potentials ◽  
Topological Quantum ◽  
The Stability ◽  
Shell Nanowires

We consider core–shell nanowires with prismatic geometry contacted with two or more superconductors in the presence of a magnetic field applied parallel to the wire. In this geometry, the lowest energy states are localized on the outer edges of the shell, which strongly inhibits the orbital effects of the longitudinal magnetic field that are detrimental to Majorana physics. Using a tight-binding model of coupled parallel chains, we calculate the topological phase diagram of the hybrid system in the presence of non-vanishing transverse potentials and finite relative phases between the parent superconductors. We show that having finite relative phases strongly enhances the stability of the induced topological superconductivity over a significant range of chemical potentials and reduces the value of the critical field associated with the topological quantum phase transition.

AHARONOV–BOHM EFFECT ON QUANTUM TRANSPORT IN SINGLE-WALLED CARBON NANOTUBE INTERFEROMETERS

2010 ◽  
Vol 24 (09) ◽  
pp. 849-857 ◽  
Author(s):  
MEI HAN ◽  
YONG ZHANG
Keyword(s):  
Magnetic Field ◽  
Gate Voltage ◽  
Axial Magnetic Field ◽  
Tight Binding ◽  
Tube Length ◽  
Quantum Conductance ◽  
Tight Binding Approximation ◽  
Single Walled Carbon ◽  
Conductance Oscillation ◽  
Walled Carbon Nanotubes

The quantum conductance of the electron interferometers composed of the armchair and metallic zigzag single-walled carbon nanotubes (SWNTs) in an axial magnetic field lower than 100 T has been studied by using the tight-binding approximation and Landauer–Buttiker formula. Quantum conductance oscillation as a function of gate voltage due to Fabry–Perot like electron interference was found. The analytical expressions of the rapid and slow conductance oscillation periods for the armchair SWNTs have been derived. It is shown that they depend on the magnetic field, gate voltage, and tube length. For the case of the metallic zigzag SWNTs, except rapid conductance oscillation, slow conductance oscillation was also found, which should not exist without the axial magnetic field.

SYMMETRY AND ELECTRO-OPTICAL PROPERTIES OF NANOTUBES

2002 ◽  
Vol 01 (03n04) ◽  
pp. 313-325 ◽  
Author(s):  
M. DAMNJANOVIĆ ◽  
I. MILOŠEVIĆ ◽  
T. VUKOVIĆ ◽  
B. NIKOLIĆ ◽  
E. DOBARDŽIĆ
Keyword(s):  
Carbon Nanotubes ◽  
Optical Properties ◽  
Density Functional ◽  
Tight Binding ◽  
Optical Characteristics ◽  
Optical Transitions ◽  
Matrix Elements ◽  
Selection Rules ◽  
Single Wall Carbon ◽  
Quantum Numbers

The symmetry of single-wall carbon and inorganic tubes is reviewed. For the carbon nanotubes it is used to get the full set of quantum numbers, in the efficient precision (combined density functional and tight-binding methods) calculation of electronic bands and their complete assignation, to obtain the selection rules for optical transitions and the momenta matrix elements for the Bloch eigen-states. The optical characteristics are thoroughly found, and discussed.

scholarly journals Inverse Faraday effect in a relativistic laser channel

2001 ◽  
Vol 19 (1) ◽  
pp. 133-136 ◽  
Author(s):  
I. KOSTYUKOV ◽  
G. SHVETS ◽  
N.J. FISCH ◽  
J.M. RAX
Keyword(s):  
Magnetic Field ◽  
Angular Momentum ◽  
Laser Radiation ◽  
Laser Pulse ◽  
Faraday Effect ◽  
Plasma Channel ◽  
Axial Magnetic Field ◽  
Absorbed Energy ◽  
Circularly Polarized ◽  
Inverse Faraday Effect

Interaction between energetic electrons and a circularly polarized laser pulse in a relativistic plasma channel is studied. Laser radiation can be resonantly absorbed by electrons executing betatron oscillations in the channel and absorbing angular momentum from the laser. The absorbed angular momentum manifests itself as a strong axial magnetic field (inverse Faraday effect). The magnitude of this magnetic field is calculated and related to the amount of the absorbed energy.

Electronic modes in carbon nanotubes with single and double impurity sites

2017 ◽  
Vol 31 (29) ◽  
pp. 1750220
Author(s):  
P. G. Komorowski ◽  
M. G. Cottam
Keyword(s):  
Carbon Nanotubes ◽  
Nearest Neighbor ◽  
Tight Binding ◽  
Longitudinal Axis ◽  
Binding Model ◽  
Substitutional Impurity ◽  
Impurity Atoms ◽  
Spatial Configurations ◽  
Impurity Sites ◽  
Walled Carbon Nanotubes

A theoretical study of isolated and doubly-clustered impurities is presented for the electronic excitations in a carbon nanotube lattice. Using a matrix operator formalism and a tight-binding model where the interactions between atoms take place via nearest-neighbor hopping, the properties of the excitations are deduced. A geometry consisting of long, single-walled carbon nanotubes is assumed with the defects introduced in the form of substitutional impurity atoms, giving rise to the localized electronic modes of the nanotube as well as the propagating modes of the pure (host) material. The impurities are assumed to be in a low concentration, having the form of either a single, isolated defect or a small cluster of two defects close together. A tridiagonal matrix technique is employed within a Green’s function formalism to obtain the properties of the discrete modes of the system, including their frequencies and localization. The numerical examples show a dependence on the nanotube diameters and on the relative spatial configurations of the impurities. The results contrast with the previous studies of line impurities since there is no translational symmetry along the longitudinal axis of the nanotubes in the present case.

Band structures of carbon nanotubes: the sp3s* tight-binding model

2001 ◽  
Vol 13 (13) ◽  
pp. L271-L275 ◽  
Author(s):  
J X Cao ◽  
X H Yan ◽  
J W Ding ◽  
D L Wang
Keyword(s):  
Carbon Nanotubes ◽  
Tight Binding ◽  
Tight Binding Model ◽  
Band Structures ◽  
Binding Model
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