Electron-Phonon Interactions and Vibrational Modes in Insulating Nanocrystals

2010 ◽  
Vol 11 ◽  
pp. 131-137
Author(s):  
M.G. Ha ◽  
E.D. Jeong ◽  
K.S. Hong ◽  
H.S. Yang
Keyword(s):  
Particle Size ◽  
Phonon Spectrum ◽  
Acoustic Phonon ◽  
Size Dependence ◽  
Electronic States ◽  
Vibrational Modes ◽  
Phonon Interaction ◽  
Electron Phonon Interaction ◽  
Isotropic Sphere

The temperature and particle size dependence of the holewidths for the 7F0 → 5D0 transition of Eu3+ ions in Eu2O3 are calculated and compared with experiment. The calculation is able to describe the effect of nanocrystal vibrational modes on the dephasing of the electronic states of probe ions. The nanocrystal was treated as an elastically isotropic sphere from which the acoustic phonon displacements and phonon spectrum were calculated. Then we applied this to the temperature and size dependencies of the electron-phonon interaction. Also the vibrational modes in nanocrystals are discussed.

Peculiarities of the Electron-Phonon Interaction in Graphite Containing Metallic Intercalated Layers

2010 ◽  
Vol 297-301 ◽  
pp. 75-81 ◽  
Author(s):  
Alexander Feher ◽  
S.B. Feodosyev ◽  
I.A. Gospodarev ◽  
V.I. Grishaev ◽  
K.V. Kravchenko ◽  
...  
Keyword(s):  
Jacobi Matrix ◽  
Local Density ◽  
Dynamic Properties ◽  
Electronic States ◽  
Bcs Theory ◽  
Phonon Interaction ◽  
Electron Phonon Interaction ◽  
Density Of Electronic States ◽  
Eliashberg Equation ◽  
Phonon Spectra

The calculation of the local density of electronic states of graphene with vacancies, using the method of Jacobi matrix, was performed. It was shown that for atoms in the sublattice with a vacancy the local density of electronic states conserves the Dirac singularity, similarly as in an ideal graphene. A quasi-Dirac singularity was observed also in the phonon spectra of graphite for the atom displacements in the direction perpendicular to layers. Changes of phonon spectra of graphite intercalated with various metals were analyzed. On the basis of our results and using the BCS theory and Eliashberg equation we proposed what dynamic properties an intercalated graphite system should show to obtain an increased Tc.

Phonon spectrum and electron-phonon interaction in technetium

2005 ◽  
Vol 31 (5) ◽  
pp. 449-453 ◽  
Author(s):  
S. M. Sichkar ◽  
V. N. Antonov
Keyword(s):  
Phonon Spectrum ◽  
Phonon Interaction ◽  
Electron Phonon Interaction

THE TEMPERATURE DEPENDENCE OF THE ENERGY LEVELS OF SHALLOW DONOR IMPURITIES IN SILICON

1967 ◽  
Vol 45 (4) ◽  
pp. 1421-1438 ◽  
Author(s):  
C. Y. Cheung ◽  
Robert Barrie
Keyword(s):  
Temperature Dependence ◽  
Energy Levels ◽  
Electronic States ◽  
Shallow Donor ◽  
Phonon Interaction ◽  
Electron Phonon Interaction ◽  
Doped Silicon ◽  
Phosphorus Doped

A calculation is made of the temperature dependence of the energy levels of shallow donor impurities in silicon. This temperature dependence arises from the electron–phonon interaction and we consider mixing only of the {1s}, {2s), and {2p0} electronic states. A comparison is made with experiment for the case of phosphorus-doped silicon.

SIZE-DEPENDENCE OF INFRARED SPECTRA IN NIOBIUM CARBIDE NANOCRYSTALS

2012 ◽  
Vol 23 (08) ◽  
pp. 1240001 ◽  
Author(s):  
V. ALVIN SHUBERT ◽  
STEVEN P. LEWIS
Keyword(s):  
Density Functional Theory ◽  
Particle Size ◽  
Density Functional ◽  
Size Dependence ◽  
Niobium Carbide ◽  
Structural Features ◽  
Particle Sizes ◽  
Vibrational Modes ◽  
Functional Theory ◽  
Ir Spectroscopic

Niobium carbide nanocrystals of ~1:1 stoichiometry have recently been observed for particle sizes ranging from Nb4C4 to Nb50C50 . Infrared (IR) spectroscopic measurements show that a new band of IR vibrational modes appears with increasing particle size at Nb9C9 . Using density-functional theory, we show that the vibrational modes in the new band involve structural features present only in nanocrystals with three or more atomic layers in every direction. The Nb9C9 nanocrystal is right at this structural threshold.

scholarly journals Effect of electron-phonon interaction on the formation of one-dimensional electronic states in coupled Cl vacancies

2015 ◽  
Vol 91 (23) ◽  
Author(s):  
Bruno Schuler ◽  
Mats Persson ◽  
Sami Paavilainen ◽  
Niko Pavliček ◽  
Leo Gross ◽  
...  
Keyword(s):  
Electronic States ◽  
Phonon Interaction ◽  
One Dimensional ◽  
Electron Phonon Interaction

Bailyn’s exchange correlation and phonon spectrum of sodium

1965 ◽  
Vol 283 (1394) ◽  
pp. 394-402 ◽  
Keyword(s):  
Phonon Spectrum ◽  
Arbitrary Constant ◽  
The Other ◽  
Arbitrary Parameter ◽  
Matrix Elements ◽  
Phonon Interaction ◽  
Interference Factor ◽  
Exchange Correlation ◽  
Specific Heats ◽  
Electron Phonon Interaction

The phonon spectrum of sodium has been calculated by using Bailyn’s matrix elements for the electron-phonon interaction. There is satisfactory agreement with the experimental results of neutron scattering, specific heats, and elastic constants. An earlier work of the authors based on Toya’s matrix elements also gave nearly the same results. It employed an arbitrary constant α in the argument of the interference factor ( ‘g’ function). Bailyn’s expression has no arbitrary parameter and has, therefore, distinct advantages over the other.

Optical Vibrational Modes and Electron-Phonon Interaction in GaAs Quantum Wells

1984 ◽  
Vol 53 (13) ◽  
pp. 1280-1283 ◽  
Author(s):  
J. E. Zucker ◽  
A. Pinczuk ◽  
D. S. Chemla ◽  
A. Gossard ◽  
W. Wiegmann
Keyword(s):  
Quantum Wells ◽  
Vibrational Modes ◽  
Phonon Interaction ◽  
Electron Phonon Interaction

scholarly journals Influence of the electron-phonon iinteraction on phonon heat conduction in a molecular nanowire

2006 ◽  
Vol 38 (2) ◽  
pp. 125-129
Author(s):  
Slobodanka Galovic ◽  
D. Cevizovic ◽  
S. Zekovic ◽  
Z. Ivic
Keyword(s):  
Heat Conduction ◽  
Dispersion Relation ◽  
Acoustic Phonon ◽  
Phonon Dispersion ◽  
Phonon Interaction ◽  
Electron Phonon Interaction ◽  
Phonon Dispersion Relation

A model for phonon heat conduction in a molecular nanowire is developed. The calculation takes into account modification of the acoustic phonon dispersion relation due to the electron-phonon interaction. The results obtained are compared with models based upon a simpler, Callaway formula.

The Gap Function in YBa2Cu3O7

1998 ◽  
Vol 12 (29n31) ◽  
pp. 3057-3062 ◽  
Author(s):  
G. L. Zhao ◽  
D. Bagayoko
Keyword(s):  
Electronic Structure ◽  
Transition Temperature ◽  
Energy Gap ◽  
Electronic States ◽  
Gap Function ◽  
Interaction Matrix ◽  
Matrix Elements ◽  
Phonon Interaction ◽  
Gap Equation ◽  
Electron Phonon Interaction

We have solved the four-dimensional anisotropic Eliashberg gap equation for YBa2Cu3O7 (YBCO) using the calculated electronic structure and the electron–phonon interaction matrix elements. The calculated T c for YBCO is about 89 K or μ*= 0.1. At or slightly above the transition temperature T c , the real part of the gap function Δ(k, 0), for all the k-points on the Fermi surface, becomes zero and the material is not superconducting. However, the energy gap function Δ(k,ω) is still nonzero for ω > 0 for some electronic states, leading to a pseudo-gap behavior in YBCO.

Sign in / Sign up

Export Citation Format

Share Document