Tight-binding vibrational analysis of single-wall carbon nanotubes

2015 ◽  
Author(s):  
Titus A. Beu ◽  
Alexandra Farcaş
Keyword(s):  
Carbon Nanotubes ◽  
Tight Binding ◽  
Vibrational Analysis ◽  
Single Wall Carbon Nanotubes ◽  
Single Wall Carbon

THE ROLE OF POTENTIAL FUNCTIONS IN THE MECHANICAL BEHAVIOR OF THE SINGLE WALL CARBON NANOTUBES

2012 ◽  
Vol 11 (03) ◽  
pp. 1240009 ◽  
Author(s):  
KEKA TALUKDAR ◽  
APURBA KRISHNA MITRA
Keyword(s):  
Mechanical Properties ◽  
Carbon Nanotubes ◽  
Tensile Strength ◽  
Interatomic Potential ◽  
Tight Binding ◽  
Flow Region ◽  
Potential Functions ◽  
Dynamics Simulation ◽  
Single Wall Carbon Nanotubes ◽  
Single Wall Carbon

Carbon nanotubes have been identified as the promising agents in reinforcing composite materials to achieve desired mechanical properties. In this study, three different types of single wall carbon nanotubes (SWCNTs) are subjected to molecular dynamics simulation to investigate their mechanical properties taking different interatomic potential functions. With unmodified Brenner's 2nd generation potential, a brittle fracture for all the SWCNTs is observed. But in tight-binding approach, the chiral and armchair SWCNTs exhibit somewhat extended plastic flow region before failure. With unmodified Brenner's potential, high tensile strength and ductility are observed for the armchair and chiral tubes. Y value of these two tubes is less than 1 TPa but more than 1 TPa for a zigzag tube. Much decrease of tensile strength and strain are noticed when we apply smoothing of the Brenner's potential at cut-off region. Failure stresses are dropped to much lower values for the three tubes. Ductility of the armchair and chiral tubes are also affected considerably by the choice of potential. Applying smoothing in the cut-off region to conserve the energy, the results show better agreement with the experimental findings.

Chirality dependence of exciton effects in single-wall carbon nanotubes: Tight-binding model

2007 ◽  
Vol 75 (3) ◽  
Author(s):  
J. Jiang ◽  
R. Saito ◽  
Ge. G. Samsonidze ◽  
A. Jorio ◽  
S. G. Chou ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Tight Binding ◽  
Single Wall Carbon Nanotubes ◽  
Tight Binding Model ◽  
Binding Model ◽  
Single Wall Carbon

EXCITONS IN SINGLE-WALL CARBON NANOTUBES

2003 ◽  
Vol 02 (06) ◽  
pp. 521-526 ◽  
Author(s):  
K. A. BULASHEVICH ◽  
R. A. SURIS ◽  
S. V. ROTKIN
Keyword(s):  
Carbon Nanotubes ◽  
Binding Energy ◽  
Dielectric Function ◽  
Energy Gap ◽  
Random Phase ◽  
Tight Binding ◽  
Exciton Binding Energy ◽  
Single Wall Carbon Nanotubes ◽  
Tight Binding Approximation ◽  
Single Wall Carbon

Excitonic states in single-wall carbon nanotubes have been studied within the tight-binding approximation. An analytical expression for the dielectric function of the nanotube has been obtained in the random phase approximation. It was demonstrated that calculations with the static dielectric function yield an overestimated exciton binding energy exceeding the nanotube energy gap. Self-consistent calculation of the exciton binding energy with the frequency-dependent dielectric function has been performed. The binding energy to energy gap ratio has been shown to have no dependence on the nanotube radius and to be a universal constant ~0.87 for given resonance integral γ0=2.7 eV .

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