Thermoelectric properties of a nanocontact made of two-capped single-wall carbon nanotubes calculated within the tight-binding approximation

2006 ◽  
Vol 73 (8) ◽  
Author(s):  
Keivan Esfarjani ◽  
Mona Zebarjadi ◽  
Yoshiyuki Kawazoe
Keyword(s):  
Carbon Nanotubes ◽  
Thermoelectric Properties ◽  
Tight Binding ◽  
Single Wall Carbon Nanotubes ◽  
Tight Binding Approximation ◽  
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 .

THE BAND-GAP AND TRUE BAND-GAP IN NOMINALLY METALLIC CARBON NANOTUBES: THE TIGHT-BINDING STUDY ON CORRUGATION EFFECT

2014 ◽  
Vol 28 (08) ◽  
pp. 1450018
Author(s):  
HONGXIA LU ◽  
JIANBAO WU ◽  
JIZHEN WANG ◽  
SHAOCONG SHI ◽  
WEIYI ZHANG
Keyword(s):  
Carbon Nanotubes ◽  
Total Energy ◽  
Band Gap ◽  
Tight Binding ◽  
Small Radius ◽  
Single Wall Carbon Nanotubes ◽  
Curvature Effect ◽  
Tight Binding Approximation ◽  
Energy Calculations ◽  
Small Band

In this paper, the band-gap and true band-gap are analyzed for the corrugated structures of various types of single wall carbon nanotubes (SWCNTs) within the tight binding approximation. We show that corrugation, combined with curvature effect, yields naturally the true small band-gap in all SWCNTs with small radius. The more stable corrugated structures of SWCNTs are backed by the abinitio total energy calculations for nominally metallic armchair SWCNTs.

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.

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