Acoustic phonon modes in asymmetric AlxGa1−xN/GaN/AlyGa1−yN quantum wells

2017 ◽  
Vol 102 ◽  
pp. 64-73 ◽  
Author(s):  
Y.H. Zan ◽  
S.L. Ban ◽  
Y.J. Chai ◽  
Y. Qu
Keyword(s):  
Quantum Wells ◽  
Acoustic Phonon ◽  
Phonon Modes

scholarly journals Parametric resonance of acoustic and optical phonons in GaAs/GaAsAl quantum well in the presence of laser field

2021 ◽  
Vol 13 (1) ◽  
pp. 7
Author(s):  
Dung Tien Nguyen ◽  
Le Canh Trung ◽  
Pham Thi Hoai Duong ◽  
Tran Cong Phong
Keyword(s):  
Quantum Well ◽  
Quantum Wells ◽  
San Francisco ◽  
Parametric Resonance ◽  
Acoustic Phonon ◽  
Parametric Amplification ◽  
Optical Phonons ◽  
Acoustic Phonons ◽  
Phonon Modes ◽  
Threshold Amplitude

In this paper, we analytically investigated the possibility of parametric resonance of acoustic and optical phonons. We obtained a general dispersion equation for parametric amplification and transformation of phonons. The dispersions of the resonant acoustic phonon modes and the threshold amplitude of the field for acoustic phonon parametric amplification are obtained. The parametric amplification for acoustic phonons in a GaAs/GaAsAl quantum well can occur under the condition that the amplitude of the external electromagnetic field is higher than the threshold amplitude. Full Text: PDF ReferencesB. A. Glavin, V. A. Kochelap, T. L. Linnik, P. Walker, A. J. Kent and M. Henini, "Monochromatic terahertz acoustic phonon emission from piezoelectric superlattices", Journal of Physics: Conference Series, Vol 92, (2007). CrossRef O. A. C. Nunes, "Piezoelectric surface acoustical phonon amplification in graphene on a GaAs substrate", Journal of Applied Physics 115, 233715 (2014). CrossRef Yu. E. Lozovik, S. P. Merkulova, I. V. Ovchinnikov, "Sasers: resonant transitions in narrow-gap semiconductors and in exciton system in coupled quantum wells", Phys. Lett. A 282, 407-414, (2001). CrossRef R.P. Beardsley, A.V. Akimov, M. Henini and A.J. Kent, "Coherent Terahertz Sound Amplification and Spectral Line Narrowing in a Stark Ladder Superlattice", PRL 104, 085501, (2010). CrossRef Pascal Ruello, Vitalyi E. Gusev, "Physical mechanisms of coherent acoustic phonons generation by ultrafast laser action", Ultrasonics 56, 21-35, (2015). CrossRef L. Esaki, in Proc. 17th Int. Conf. Phys. Semiconductors, San Francisco, CA, Aug, J.D. Chadi and W.A. Harrison, Eds, Berlin: Springer- Verlag, 473, (1984). DirectLink W. Xu, F. M. Peeters and J. T. Devreese, "Electrophonon resonances in a quasi-two-dimensional electron system", Phys. Rev. B 48, 1562 (1993). CrossRef Tran Cong Phong, Nguyen Quang Bau, "Parametric resonance of acoustic and optical phonons in a quantum well", Journal of the Korean Physical Society, Vol. 42, No. 5, 647-651, (2003). DirectLink

Quantized Acoustic-Phonon Modes in Metallic Nanowire Structures

2015 ◽  
Vol 44 (12) ◽  
pp. 3019-3022 ◽  
Author(s):  
Hou Yuexia ◽  
Xu Wen ◽  
Hu Jiaguang ◽  
Xiao Yiming
Keyword(s):  
Acoustic Phonon ◽  
Phonon Modes

Guided Acoustic Phonon Modes in Layered Anisotropic Nanowires

2003 ◽  
Author(s):  
Osama M. Mukdadi ◽  
Subhendu K. Datta ◽  
Martin L. Dunn
Keyword(s):  
Thermal Conductivity ◽  
Acoustic Phonon ◽  
Energy Transport ◽  
Bulk Material ◽  
Rectangular Cross Section ◽  
Critical Role ◽  
Acoustic Phonons ◽  
Phonon Modes ◽  
Low Velocity ◽  
Analysis Technique

Acoustic phonons play a critical role in energy transport in nanostructures. The dispersion of acoustic phonons strongly influences thermal conductivity. Recent observations show lower values of thermal conductivity in finite dimensional nanostructures than in the bulk material. In this work, we will present results for guided acoustic phonon modes in (a) a bilayered GaAs-Nb nanowire of rectangular cross section and (b) a trapezoidal Si nanowire. The former has been used for phonon counting in a nanocalorimeter for measuring thermal conductivity and the latter is commonly used in MEMS applications. A semi-analytical finite element (SAFE) analysis technique has been used to investigate the effects of layering, anisotropy, and boundaries on the dispersion of modes of propagation. Many interesting features of group velocities are found that show confinements around the corners, in the low velocity layer, and coupling of the longitudinal and flexural modes. These would strongly influence thermal conductivity and might provide means of nondestrutive evaluation of mechanical properties.

Resonant one-acoustic-phonon Raman scattering in multiple quantum wells

1992 ◽  
Vol 84 (11) ◽  
pp. 1039-1042 ◽  
Author(s):  
V.F Sapega ◽  
V.I Belitsky ◽  
A.J Shields ◽  
T Ruf ◽  
M Cardona ◽  
...  
Keyword(s):  
Raman Scattering ◽  
Quantum Wells ◽  
Acoustic Phonon ◽  
Multiple Quantum Wells ◽  
Multiple Quantum

scholarly journals Acoustic phonon lifetimes limit thermal transport in methylammonium lead iodide

2018 ◽  
Vol 115 (47) ◽  
pp. 11905-11910 ◽  
Author(s):  
Aryeh Gold-Parker ◽  
Peter M. Gehring ◽  
Jonathan M. Skelton ◽  
Ian C. Smith ◽  
Dan Parshall ◽  
...  
Keyword(s):  
Lattice Dynamics ◽  
Acoustic Phonon ◽  
Optoelectronic Devices ◽  
High Energy ◽  
High Energy Resolution ◽  
Phonon Coupling ◽  
Lead Iodide ◽  
Phonon Modes ◽  
Electron Phonon Coupling ◽  
Methylammonium Lead Iodide

Hybrid organic–inorganic perovskites (HOIPs) have become an important class of semiconductors for solar cells and other optoelectronic applications. Electron–phonon coupling plays a critical role in all optoelectronic devices, and although the lattice dynamics and phonon frequencies of HOIPs have been well studied, little attention has been given to phonon lifetimes. We report high-precision momentum-resolved measurements of acoustic phonon lifetimes in the hybrid perovskite methylammonium lead iodide (MAPI), using inelastic neutron spectroscopy to provide high-energy resolution and fully deuterated single crystals to reduce incoherent scattering from hydrogen. Our measurements reveal extremely short lifetimes on the order of picoseconds, corresponding to nanometer mean free paths and demonstrating that acoustic phonons are unable to dissipate heat efficiently. Lattice-dynamics calculations using ab initio third-order perturbation theory indicate that the short lifetimes stem from strong three-phonon interactions and a high density of low-energy optical phonon modes related to the degrees of freedom of the organic cation. Such short lifetimes have significant implications for electron–phonon coupling in MAPI and other HOIPs, with direct impacts on optoelectronic devices both in the cooling of hot carriers and in the transport and recombination of band edge carriers. These findings illustrate a fundamental difference between HOIPs and conventional photovoltaic semiconductors and demonstrate the importance of understanding lattice dynamics in the effort to develop metal halide perovskite optoelectronic devices.

scholarly journals Многократное изменение электрон-фононного взаимодействия в квантовых ямах с диэлектрически различными барьерами

2022 ◽  
Vol 56 (1) ◽  
pp. 101
Author(s):  
А.Ю. Маслов ◽  
О.В. Прошина
Keyword(s):  
Quantum Wells ◽  
Charged Particles ◽  
Strong Interactions ◽  
Asymmetric Structure ◽  
Optical Phonons ◽  
Phonon Modes ◽  
Phonon Interaction ◽  
Barrier Materials ◽  
Electron Phonon Interaction ◽  
Order Of Magnitude

Abstract The specific features of the interaction of charged particles with polar optical phonons have been studied theoretically for quantum wells with the barriers that are asymmetric in their dielectric properties. It is shown that the interaction with interface phonon modes makes the greatest contribution in narrow quantum wells. The parameters of the electron-phonon interaction were found for the cases of different values of the phonon frequencies in the barrier materials. It turned out that a significant (by almost an order of magnitude) change in the parameters of the electron-phonon interaction can occur in such structures. This makes it possible, in principle, to trace the transition from weak to strong interactions in quantum wells of the same type but with different compositions of barrier materials. The conditions are found under which an enhancement of the electron-phonon interaction is possible in an asymmetric structure in comparison with a symmetric one with the barriers of the same composition.

POLAR VIBRATION SPECTRA OF INTERFACE AND SURFACE OPTICAL PHONONS AND THEIR FRÖHLICH ELECTRON-PHONON INTERACTIONS IN FREESTANDING SYMMETRICAL AND ASYMMETRICAL WURTZITEGaN/Ga1-xAlxNMULTI-LAYER HETEROSTRUCTURES

2006 ◽  
Vol 20 (05) ◽  
pp. 559-578 ◽  
Author(s):  
LI ZHANG ◽  
JUN-JIE SHI
Keyword(s):  
Quantum Wells ◽  
Electrostatic Potential ◽  
Uniaxial Crystal ◽  
Wave Number ◽  
Phonon Modes ◽  
Electron Phonon Interaction ◽  
Surface Optical ◽  
Electron Phonon Coupling ◽  
Crystal Model ◽  
Dielectric Continuum

Under the dielectric continuum model and Loudon's uniaxial crystal model, by adopting the transfer matrix method, the dispersion properties of the interface optical (IO) and surface optical (SO) phonon modes and their couplings with electrons in multi-layer coupling wurtzite quantum wells (QWs) are deduced and analyzed via the method of electrostatic potential expanding. Numerical calculations on a freestanding symmetrical wurtzite QW and an asymmetrical wurtzite QW have been performed. Results reveal that, in general, there are four branches of IO and two branches of SO phonon modes in the systems. The dispersions of these IO and SO phonon modes are obvious only when the free two-dimensional phonon wave number ktparallel to the heterostructure interfaces is small. The degenerating behavior for these phonon modes has been clearly observed for small kt. When ktis relatively large, with the increase in kt, the frequencies of the IO and SO phonon modes converge to some definite limiting frequencies in corresponding wurtzite single planar heterostructure. This feature have been analyzed in depth from the mathematical and physical viewpoints. The calculations of electron-phonon coupling function show that, the electrostatic potential distribution of the IO and SO mode in freestanding symmetrical wurtzite QW is either symmetrical or is antisymmetrical; but that in freestanding asymmetrical wurtzite QW is neither symmetrical nor is antisymmetric. The calculation also shows that the SO modes and the short wavelength phonon modes play a more important role in the electron-phonon interaction.

Excitation and detection of surface acoustic phonon modes inAu/Al2O3multilayers

2009 ◽  
Vol 80 (16) ◽  
Author(s):  
A. Halabica ◽  
S. T. Pantelides ◽  
R. F. Haglund ◽  
R. H. Magruder ◽  
A. Meldrum
Keyword(s):  
Acoustic Phonon ◽  
Phonon Modes
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