Edge singularity in tight binding approximation

1972 ◽  
Vol 33 (11-12) ◽  
pp. 1081-1088 ◽  
Author(s):  
P. Joyes
2016 ◽  
Vol 15 (05n06) ◽  
pp. 1660009 ◽  
Author(s):  
Keka Talukdar ◽  
Anil Shantappa

Carbon nanotubes (CNTs) have been proved to have promising applicability in various fields of science and technology. Their fascinating mechanical, electrical, thermal, optical properties have caught the attention of today’s world. We have discussed here the great possibility of using CNTs in electronic devices. CNTs can be both metallic and semiconducting depending on their chirality. When two CNTs of different chirality are joined together via topological defects, they may acquire rectifying diode property. We have joined two tubes of different chiralities through circumferential Stone–Wales defects and calculated their density of states by nearest neighbor tight binding approximation. Transmission function is also calculated to analyze whether the junctions can be used as electronic devices. Different heterojunctions are modeled and analyzed in this study. Internal stresses in the heterojunctions are also calculated by molecular dynamics simulation.


1997 ◽  
Vol 486 ◽  
Author(s):  
G. Allan ◽  
C. Delerue ◽  
M. Lannoo

AbstractThe electronic structure of amorphous silicon layers has been calculated within the empirical tight binding approximation using the Wooten-Winer-Weaire atomic structure model. We predict an important blue shift due to the confinement for layer thickness below 3 nm and we compare with crystalline silicon layers. The radiative recombination rate is enhanced by the disorder and the confinement but remains quite small. The comparison of our results with experimental results shows that the density of defects and localized states in the studied samples must be quite small.


2010 ◽  
Vol 24 (09) ◽  
pp. 849-857 ◽  
Author(s):  
MEI HAN ◽  
YONG ZHANG

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.


1997 ◽  
Vol 19 (4) ◽  
pp. 261-263
Author(s):  
M. A. Grado-Caffaro ◽  
M. Grado-Caffaro

A formulation for the paramagnetic susceptibility of a typical disordered itinerant-electron metamagnetic material is proposed by using a tight-binding approximation. Moreover, some considerations on the susceptibility tensor are exposed.


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