ON THE COUPLING BETWEEN ELECTRONS AND SOFT-MODE PHONONS IN La2CuO4

1990 ◽  
Vol 04 (07) ◽  
pp. 489-496 ◽  
Author(s):  
Z. K. PETRU ◽  
N. M. PLAKIDA
Keyword(s):  
Fermi Energy ◽  
Soft Mode ◽  
Tight Binding ◽  
Electronic Energy ◽  
Tight Binding Model ◽  
Energy Bands ◽  
Phonon Modes ◽  
Binding Model ◽  
Bond Bending ◽  
Electronic Energy Bands

An interaction between soft bond-bending phonon modes and localized 3d – 2p electrons is considered. Its strength is estimated to be of the order of 1 eV/Å. By means of the tight-binding model, the electronic energy bands of La 2 CuO 4 are calculated. It is explicitly shown that a tetragonal to orthorhombic transition does not open a gap at the Fermi energy.

Tight-binding model for the energy bands in solids

1969 ◽  
Vol 3 (3) ◽  
pp. 119-121 ◽  
Author(s):  
Jan Linderberg ◽  
Yngve Öhrn
Keyword(s):  
Tight Binding ◽  
Tight Binding Model ◽  
Energy Bands ◽  
Binding Model

Electronic Structure of Carbon Fibers based on C60

1992 ◽  
Vol 247 ◽  
Author(s):  
Riichiro Saito ◽  
Mitsutaka Fujita ◽  
G. Dresselhaus ◽  
M. S. Dresselhaus
Keyword(s):  
Carbon Fibers ◽  
Tight Binding ◽  
Electronic Energy ◽  
Rotational Axis ◽  
Structure Model ◽  
Energy Bands ◽  
Binding Model ◽  
One Dimensional ◽  
Band Structure Model ◽  
Bucky Ball

ABSTRACTThe electronic structures of some possible carbon fibers nucleated from the hemisphere of a bucky ball are presented. A one-dimensional electronic energy band structure model of such carbon fibers, having not only a principal rotational axis but also fibers with screw axes, can be derived by folding the two-dimensional energy bands of graphite. By considering the variation of the fiber diameter and helicity within a simple tight binding model calculation, we show that 1/3 of the fibers are metallic and 2/3 are semiconducting. The effect of adding multiple tubule layers is considered.

Electronic Energy Bands in γ-InSe with and without Intercalated Lithium

1990 ◽  
Vol 210 ◽  
Author(s):  
P. Gomes Da Costa ◽  
M. Balkanski ◽  
R. F. WALLIS
Keyword(s):  
Lithium Atom ◽  
Electronic Band Structure ◽  
Tight Binding ◽  
Electronic Energy ◽  
Band Gaps ◽  
Energy Bands ◽  
Energy Position ◽  
Electronic Band ◽  
Direct Band ◽  
Electronic Energy Bands

AbstractThe effect of intercalated lithium on the electronic band structure of the γ-polytype of InSe has been investigated using a tight-binding method. The energy bands of the pure polytype were calculated and the results compared with previous work. The modifications of the energy bands produced by the introduction of one lithium atom per unit cell were calculated for the lowest potential energy position of the lithium atom in the Van der Waals gap between layers. The results for the changes in the smallest and next-to-smallest direct band gaps are compared with experimental data. An interpretation of a photoluminescence peak produced by lithium intercalation is given.

A Tight Binding Model for The Electronic Structure of FCC and SC C60

1992 ◽  
Vol 06 (23n24) ◽  
pp. 3959-3963
Author(s):  
Nacir Tit ◽  
Vijay Kumar
Keyword(s):  
Lattice Constant ◽  
Tight Binding ◽  
Text Structure ◽  
Tight Binding Model ◽  
Energy Bands ◽  
Pairing Mechanism ◽  
Binding Model ◽  
Conduction Bands ◽  
Mechanism Of Superconductivity ◽  
Good Agreement

Ab-initio calculations1 for K3C60 indicate that the general features of the energy bands within LDA remain nearly unchanged as compared to C60. In the electronphonon pairing mechanism of superconductivity in these materials, the variation in Tc has been attributed to changes in the lattice constant2 which affects N(EF). We have therefore fitted the valence and conduction bands of the fcc C60, obtained by Troullier and Martins3 from an LDA plane wave basis calculations, with a tight binding model and studied the energy bands as a function of the lattice constant. As the overlap between orbitals on neighbouring balls is small, the band width is found to decrease by about 30% in going from K3C60 to Rb2CsC60. The density of states, thus, obtained is used to estimate variation in Tc from McMillan’s formula. These results are in good agreement with experimental data. Calculations of the energy bands are also presented for the low temperature [Formula: see text] structure.

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