An ad hoc tight binding method to study the electronic structure of semiconducting polymers

2009 ◽  
Vol 480 (4-6) ◽  
pp. 210-214 ◽  
Author(s):  
David P. McMahon ◽  
Alessandro Troisi
1991 ◽  
Vol 234 ◽  
Author(s):  
P. Pecheur ◽  
G. Toussaint

ABSTRACTThe electronic structure of Ru2Si3 has been calculated with the empirical tight binding method and the recursion procedure. The calculation strongly indicates that there exists a gap in the structure, which makes Ru2Si3 semiconducting, as found experimentally and explains the stability of the chimney-ladder phases for a valence electron concentration per transition metal atom smaller than 14.


1997 ◽  
Vol 493 ◽  
Author(s):  
J Robertson ◽  
C W Chen

ABSTRACTThe electronic structure of SrBi2Ta2O9 and related oxides such as SrBi2Nb2O9, Bi2WO6 and Bi3Ti4O12 have been calculated by the tight-binding method. In each case, the band gap is about 4.1 eV and the band edge states occur on the Bi-O layers and consist of mixed O p/Bi s states at the top of the valence band and Bi p states at the bottom of the conduction band. The main difference between the compounds is that Nb 5d and Ti 4d states in the Nb and Ti compounds lie lower than the Ta 6d states in the conduction band. The surface pinning levels are found to pin Schottky barriers 0.8 eV below the conduction band edge.


2015 ◽  
Vol 2015 ◽  
pp. 1-5 ◽  
Author(s):  
A. S. Kolesnikova ◽  
M. M. Slepchenkov ◽  
M. F. Lin ◽  
O. E. Glukhova

By application of empirical method it is found that graphene nanoflake (graphane) saturated by hydrogen is not elastic material. In this case, the modulus of the elastic compression of graphane depends on its size, allowing us to identify the linear parameters of graphane with maximum Young’s modulus for this material. The electronic structure of graphane nanoflakes was calculated by means of the semiempirical tight-binding method. It is found that graphane nanoflakes can be characterized as dielectric. The energy gap of these particles decreases with increasing of the length tending to a certain value. At the same time, the ionization potential of graphane also decreases. A comparative analysis of the calculated values with the same parameters of single-walled nanotubes is performed.


1996 ◽  
Vol 449 ◽  
Author(s):  
C. Noguez ◽  
R. Esquivel-Sirvent ◽  
D. R. Alfonso ◽  
S. E. Ulloa ◽  
D. A. Drabold

ABSTRACTWe present a theoretical study of the optical properties of the GaN (1010) surface. We employed a semi-empirical tight-binding method to calculate the surface electronic structure. The parameters were adjusted to reproduce the correct band structure of the bulk wurzite GaN. These parameters were interpolated to the surface using Harrison’s rule. From the surface electronic structure the surface dielectric response was obtained. The dielectric response is analized in terms of surface-surface, and surface-bulk electronic transitions.


1997 ◽  
Vol 491 ◽  
Author(s):  
M. Kohyama ◽  
N. Arai ◽  
S. Takeda

ABSTRACTComplex defects in Si and SiC such as coincidence tilt boundaries, planar defects and self-interstitial clusters were dealt with by using the transferable tight-binding method for Si and the self-consistent tight-binding method for SiC. These results have been compared with ab initio calculations of similar configurations. Essential features of the tight-binding results have been supported by the ab initio results. Especially, the agreement on stable atomic configurations is good, although there exits a tendency that energy increases are somewhat overestimated by the tight-binding methods. Serious faults have been found for the electronic structure by the tight-binding method for SiC.


2005 ◽  
Vol 19 (15n17) ◽  
pp. 2532-2537
Author(s):  
E. MARTÍNEZ ◽  
R. ROBLES ◽  
A. VEGA ◽  
R. C. LONGO ◽  
L. J. GALLEGO

The possibility of a non-collinear magnetic configuration of the Fe 3 microcluster supported on the Ni (001) surface has been investigated. The morphology of the supported cluster has been calculated by means of the modified embedded atom model with quenched molecular dynamics simulations, and the electronic structure for the most stable geometrical configuration has been studied using a self-consistent non-collinear spd tight-binding method parameterised to ab-initio tight-binding linear muffin tin orbital results. Our predictions are compared with previous results for the free-standing Fe 3 microcluster. The influence of the substrate in both the structure and the magnetic properties, particularly the onset of non-collinear magnetism, is discussed in detail.


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