Layer and bulk phonon modes in the YBa2Cu3O6 compound

1995 ◽  
Vol 245 (1-2) ◽  
pp. 48-56 ◽  
Author(s):  
Yu.E. Kitaev ◽  
L.V. Laisheva ◽  
M.F. Limonov ◽  
H. Lichtenstern ◽  
A.P. Mirgorodsky ◽  
...  
Keyword(s):  
Phonon Modes ◽  
Bulk Phonon

scholarly journals lntersubband Relaxation in Step Quantum Well Structures

VLSI Design ◽  
1998 ◽  
Vol 8 (1-4) ◽  
pp. 289-293
Author(s):  
J. P. Sun ◽  
H. B. Teng ◽  
G. I. Haddad ◽  
M. A. Stroscio ◽  
G. J. Iafrate
Keyword(s):  
Quantum Well ◽  
Form Factors ◽  
Phonon Energy ◽  
Longitudinal Optical Phonon ◽  
Relaxation Rates ◽  
Phonon Modes ◽  
Quantum Well Structures ◽  
Bulk Phonon ◽  
Interface Phonons ◽  
Intersubband Relaxation

Intersubband relaxation due to electron interactions with the localized phonon modes plays an important role for population inversion in quantum well laser structures designed for intersubband lasers operating at mid-infrared to submillimeter wavelengths. In this work, intersubband relaxation rates between subbands in step quantum well structures are evaluated numerically using Fermi's golden rule, in which the localized phonon modes including the asymmetric interface modes, symmetric interface modes, and confined phonon modes and the electron – phonon interaction Hamiltonians are derived based on the macroscopic dielectric continuum model, whereas the electron wave functions are obtained by solving the Schrödinger equation for the heterostructures under investigation. The sum rule for the relationship between the form factors of the various localized phonon modes and the bulk phonon modes is examined and verified for these structures. The intersubband relaxation rates due to electron scattering by the asymmetric interface phonons, symmetric interface phonons, and confined phonons are calculated and compared with the relaxation rates calculated using the bulk phonon modes and the Fröhlich interaction Hamiltonian for step quantum well structures with subband separations of 36 meV and 50meV, corresponding to the bulk longitudinal optical phonon energy and interface phonon energy, respectively. Our results show that for preferential electron relaxation in intersubband laser structures, the effects of the localized phonon modes, especially the interface phonon modes, must be included for optimal design of these structures.

scholarly journals High-frequency cavity optomechanics using bulk acoustic phonons

2019 ◽  
Vol 5 (4) ◽  
pp. eaav0582 ◽  
Author(s):  
Prashanta Kharel ◽  
Glen I. Harris ◽  
Eric A. Kittlaus ◽  
William H. Renninger ◽  
Nils T. Otterstrom ◽  
...  
Keyword(s):  
Ground State ◽  
High Frequency ◽  
Optical Cavity ◽  
Parametric Instability ◽  
Phonon Modes ◽  
Power Laser ◽  
Quantum Operations ◽  
Cavity Modes ◽  
Laser Oscillators ◽  
Bulk Phonon

To date, microscale and nanoscale optomechanical systems have enabled many proof-of-principle quantum operations through access to high-frequency (gigahertz) phonon modes that are readily cooled to their thermal ground state. However, minuscule amounts of absorbed light produce excessive heating that can jeopardize robust ground-state operation within these microstructures. In contrast, we demonstrate an alternative strategy for accessing high-frequency (13 GHz) phonons within macroscopic systems (centimeter scale) using phase-matched Brillouin interactions between two distinct optical cavity modes. Counterintuitively, we show that these macroscopic systems, with motional masses that are 1 million to 100 million times larger than those of microscale counterparts, offer a complementary path toward robust ground-state operation. We perform both optomechanically induced amplification/transparency measurements and demonstrate parametric instability of bulk phonon modes. This is an important step toward using these beam splitter and two-mode squeezing interactions within bulk acoustic systems for applications ranging from quantum memories and microwave-to-optical conversion to high-power laser oscillators.

BULK PHONON MODES OF YBA2CU3O7 FROM INFRARED ABSORPTION AT 300–30K.

1987 ◽  
Vol 01 (03n04) ◽  
pp. 1105-1108
Author(s):  
C. TALIANI ◽  
R. ZAMBONI ◽  
F. LICCI
Keyword(s):  
Infrared Absorption ◽  
Phonon Modes ◽  
Bulk Phonon

Bulk phonon modes of YBa2Cu3O7 from infrared absorption at 300-30K

1987 ◽  
Vol 64 (6) ◽  
pp. 911-913 ◽  
Author(s):  
C. Taliani ◽  
R. Zamboni ◽  
F. Licci
Keyword(s):  
Infrared Absorption ◽  
Phonon Modes ◽  
Bulk Phonon

Phonon Transport in Thin Films: A Lattice Dynamics/Boltzmann Transport Equation Study

2010 ◽  
Author(s):  
Daniel P. Sellan ◽  
Joseph E. Turney ◽  
Eric S. Landry ◽  
Alan J. H. McGaughey ◽  
Cristina H. Amon
Keyword(s):  
Thin Films ◽  
Thermal Conductivity ◽  
Lattice Dynamics ◽  
Boltzmann Transport Equation ◽  
Boltzmann Transport ◽  
Phonon Modes ◽  
Bulk Phonon ◽  
Plane Direction ◽  
The Cross ◽  
Phonon Properties

The cross-plane and in-plane phonon thermal conductivities of Stillinger-Weber (SW) silicon thin films are predicted using the Boltzmann transport equation under the relaxation time approximation. We model the thin films using bulk phonon properties obtained from harmonic and anharmonic lattice dynamics calculations. The cross-plane and in-plane thermal conductivities are reduced from the corresponding bulk value. This reduction is more severe for the cross-plane direction than for the in-plane direction. For the in-plane direction, we find that the predicted reduction in thermal conductivity gives a good lower bound to available experimental results. Including the effects of boundary scattering using the Matthiessen rule, which assumes that scattering mechanisms are independent, yields thermal conductivity predictions that are at most 12% lower than our more accurate results. Neglecting optical phonon modes, while valid for bulk systems, introduces 22.5% error when modeling thin films. Using phonon properties along the [001] direction (i.e., the isotropic approximation) yields bulk predictions that are 15% lower than that when all of the phonon modes are considered. For thin films, this deviation increases to 25%. Our results show that a single bulk phonon mean free path is an inadequate metric for predicting the thermal conductivity reduction in thin films.

scholarly journals Decelerated lattice excitation and absence of bulk phonon modes at surfaces: Ultra-fast electron diffraction from Bi(111) surface upon fs-laser excitation

2019 ◽  
Vol 6 (6) ◽  
pp. 065101 ◽  
Author(s):  
V. Tinnemann ◽  
C. Streubühr ◽  
B. Hafke ◽  
T. Witte ◽  
A. Kalus ◽  
...  
Keyword(s):  
Electron Diffraction ◽  
Fast Electron ◽  
Laser Excitation ◽  
Phonon Modes ◽  
Fs Laser ◽  
Bulk Phonon

Optical Control of Bulk Phonon Modes in Crystalline Solids

2021 ◽  
pp. 2100103
Author(s):  
Yuan‐Fei Gao ◽  
Jia‐Min Lai ◽  
Jun Zhang
Keyword(s):  
Optical Control ◽  
Crystalline Solids ◽  
Phonon Modes ◽  
Bulk Phonon

scholarly journals Degenerate topological line surface phonons in quasi-1D double helix crystal SnIP

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Bo Peng ◽  
Shuichi Murakami ◽  
Bartomeu Monserrat ◽  
Tiantian Zhang
Keyword(s):  
First Principles ◽  
Mirror Symmetry ◽  
Double Helix ◽  
Surface States ◽  
First Principles Calculations ◽  
Phonon Modes ◽  
One Dimensional ◽  
Topological Materials ◽  
Boundary Correspondence ◽  
Bulk Phonon

AbstractDegenerate points/lines in the band structures of crystals have become a staple of the growing number of topological materials. The bulk-boundary correspondence provides a relation between bulk topology and surface states. While line degeneracies of bulk excitations have been extensively characterised, line degeneracies of surface states are not well understood. We show that SnIP, a quasi-one-dimensional van der Waals material with a double helix crystal structure, exhibits topological nodal rings/lines in both the bulk phonon modes and their corresponding surface states. Using a combination of first-principles calculations, symmetry-based indicator theories and Zak phase analysis, we find that two neighbouring bulk nodal rings form doubly degenerate lines in their drumhead-like surface states, which are protected by the combination of time-reversal symmetry $${{{\mathcal{T}}}}$$ T and glide mirror symmetry $${\bar{M}}_{y}$$ M ¯ y . Our results indicate that surface degeneracies can be generically protected by symmetries such as $${{{\mathcal{T}}}}{\bar{M}}_{y}$$ T M ¯ y , and phonons provide an ideal platform to explore such degeneracies.

scholarly journals Phonons in Short-Period GaN/AlN Superlattices: Group-Theoretical Analysis, Ab initio Calculations, and Raman Spectra

Nanomaterials ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 286
Author(s):  
Valery Davydov ◽  
Evgenii Roginskii ◽  
Yuri Kitaev ◽  
Alexander Smirnov ◽  
Ilya Eliseyev ◽  
...  
Keyword(s):  
Theoretical Analysis ◽  
Ab Initio Calculations ◽  
Ab Initio ◽  
Raman Spectra ◽  
Density Functional ◽  
Structural Characteristics ◽  
Vibrational Modes ◽  
Phonon Modes ◽  
Short Period ◽  
Group Theoretical Analysis

We report the results of experimental and theoretical studies of phonon modes in GaN/AlN superlattices (SLs) with a period of several atomic layers, grown by submonolayer digital plasma-assisted molecular-beam epitaxy, which have a great potential for use in quantum and stress engineering. Using detailed group-theoretical analysis, the genesis of the SL vibrational modes from the modes of bulk AlN and GaN crystals is established. Ab initio calculations in the framework of the density functional theory, aimed at studying the phonon states, are performed for SLs with both equal and unequal layer thicknesses. The frequencies of the vibrational modes are calculated, and atomic displacement patterns are obtained. Raman spectra are calculated and compared with the experimental ones. The results of the ab initio calculations are in good agreement with the experimental Raman spectra and the results of the group-theoretical analysis. As a result of comprehensive studies, the correlations between the parameters of acoustic and optical phonons and the structure of SLs are obtained. This opens up new possibilities for the analysis of the structural characteristics of short-period GaN/AlN SLs using Raman spectroscopy. The results obtained can be used to optimize the growth technologies aimed to form structurally perfect short-period GaN/AlN SLs.

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