Phonon Spectra of Ultrathin GaAs/AlAs Superlattices

1991 ◽  
pp. 39-52 ◽  
Author(s):  
E. Molinari ◽  
S. Baroni ◽  
P. Giannozzi ◽  
S. de Gironcoli
Keyword(s):  
Phonon Spectra

Manifestation of defects in phonon spectra of binary zinc-blende compounds

2004 ◽  
Vol 27 (1-3) ◽  
pp. 321-324 ◽  
Author(s):  
J. Polit ◽  
E. M. Sheregii ◽  
J. Cebulski ◽  
M. Pociask ◽  
A. Kisiel ◽  
...  
Keyword(s):  
Zinc Blende ◽  
Phonon Spectra

FIRST PRINCIPLES CALCULATION OF THE PHONON SPECTRA OF SOLIDS

1981 ◽  
Vol 42 (C6) ◽  
pp. C6-625-C6-627 ◽  
Author(s):  
P. E. Van Camp ◽  
V. E. Van Doren ◽  
J. T. Devreese
Keyword(s):  
First Principles ◽  
First Principles Calculation ◽  
Phonon Spectra

scholarly journals Frequency-domain study of nonthermal gigahertz phonons reveals Fano coupling to charge carriers

2020 ◽  
Vol 6 (51) ◽  
pp. eabd4540
Author(s):  
Thomas Vasileiadis ◽  
Heng Zhang ◽  
Hai Wang ◽  
Mischa Bonn ◽  
George Fytas ◽  
...  
Keyword(s):  
Frequency Domain ◽  
Acoustic Waves ◽  
Lamb Waves ◽  
Charge Carriers ◽  
Acoustic Phonons ◽  
Phonon Spectra ◽  
Electron Hole Plasma ◽  
Nonequilibrium Conditions ◽  
Microelectronic Components ◽  
Anti Stokes

Telecommunication devices exploit hypersonic gigahertz acoustic phonons to mediate signal processing with microwave radiation, and charge carriers to operate various microelectronic components. Potential interactions of hypersound with charge carriers can be revealed through frequency- and momentum-resolved studies of acoustic phonons in photoexcited semiconductors. Here, we present an all-optical method for excitation and frequency-, momentum-, and space-resolved detection of gigahertz acoustic waves in a spatially confined model semiconductor. Lamb waves are excited in a bare silicon membrane using femtosecond optical pulses and detected with frequency-domain micro-Brillouin light spectroscopy. The population of photoexcited gigahertz phonons displays a hundredfold enhancement as compared with thermal equilibrium. The phonon spectra reveal Stokes–anti-Stokes asymmetry due to propagation, and strongly asymmetric Fano resonances due to coupling between the electron-hole plasma and the photoexcited phonons. This work lays the foundation for studying hypersonic signals in nonequilibrium conditions and, more generally, phonon-dependent phenomena in photoexcited nanostructures.

LATTICE DYNAMICS OF THE BINARY APERIODIC CHAINS OF ATOMS I: FRACTAL DIMENSION OF PHONON SPECTRA

1995 ◽  
Vol 09 (12) ◽  
pp. 1429-1451 ◽  
Author(s):  
WŁODZIMIERZ SALEJDA
Keyword(s):  
Fractal Dimension ◽  
Lattice Dynamics ◽  
Nearest Neighbor ◽  
Average Distance ◽  
Local Maximum ◽  
Fractal Dimensions ◽  
Dimension Formula ◽  
Phonon Spectra ◽  
Wide Range ◽  
Silver Mean

The microscopic harmonic model of lattice dynamics of the binary chains of atoms is formulated and studied numerically. The dependence of spring constants of the nearest-neighbor (NN) interactions on the average distance between atoms are taken into account. The covering fractal dimensions [Formula: see text] of the Cantor-set-like phonon spec-tra (PS) of generalized Fibonacci and non-Fibonaccian aperiodic chains containing of 16384≤N≤33461 atoms are determined numerically. The dependence of [Formula: see text] on the strength Q of NN interactions and on R=mH/mL, where mH and mL denotes the mass of heavy and light atoms, respectively, are calculated for a wide range of Q and R. In particular we found: (1) The fractal dimension [Formula: see text] of the PS for the so-called goldenmean, silver-mean, bronze-mean, dodecagonal and Severin chain shows a local maximum at increasing magnitude of Q and R>1; (2) At sufficiently large Q we observe power-like diminishing of [Formula: see text] i.e. [Formula: see text], where α=−0.14±0.02 and α=−0.10±0.02 for the above specified chains and so-called octagonal, copper-mean, nickel-mean, Thue-Morse, Rudin-Shapiro chain, respectively.

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.

The phonon spectra and vibrational thermodynamical properties of Cu vicinal surfaces

2002 ◽  
Vol 519 (1-2) ◽  
pp. 15-32 ◽  
Author(s):  
C Barreteau ◽  
F Raouafi ◽  
M.C Desjonquères ◽  
D Spanjaard
Keyword(s):  
Vicinal Surfaces ◽  
Thermodynamical Properties ◽  
Phonon Spectra

Ab initio phonon spectra from a supercell approach

1999 ◽  
Vol 263-264 ◽  
pp. 432-435 ◽  
Author(s):  
R Heid ◽  
K.-P Bohnen ◽  
W Reichardt
Keyword(s):  
Ab Initio ◽  
Phonon Spectra
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