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We report the results of the study of the acoustic and optical phonons in Si-doped AlN thin films grown by metalorganic chemical vapor deposition on sapphire substrates. The Brillouin - Mandelstam and Raman light scattering spectroscopies…

We report results of Brillouin - Mandelstam spectroscopy of transparent alumina crystals with Nd dopants. The ionic radius and atomic mass of Nd atoms are distinctively different from those of the host Al atoms. Our results show that even a…

Phonons-quantized vibrational modes in crystalline structures-govern phenomena ranging from thermal and mechanical transport to quantum mechanics. In recent years, a new class of artificial materials called phononic crystals has emerged,…

Mesoscale and Nanoscale Physics · Physics 2024-12-03 Michele Diego , Roman Anufriev , Ryoto Yanagisawa , Masahiro Nomura

The vibrational density of states of silicon nanoparticles in the range from 2.3 to 10.3 nm is studied with the help of molecular-dynamics simulations. From these simulations the vibrational density of states and frequencies of bulk-like…

Materials Science · Physics 2011-01-20 R. Meyer , D. Comtesse

We report results of a combined investigation of thermal conductivity and acoustic phonon spectra in nanoporous alumina membranes with the pore diameter decreasing from D=180 nm to 25 nm. The samples with the hexagonally arranged pores were…

Mesoscale and Nanoscale Physics · Physics 2016-02-01 Fariborz Kargar , Sylvester Ramirez , Bishwajit Debnath , Hoda Malekpour , Roger Lake , Alexander A. Balandin

While nanoscale modal confinement radically enhances a variety of nonlinear light-matter interactions within silicon waveguides, traveling-wave stimulated Brillouin scattering nonlinearities have never been observed in silicon…

Stimulated Brillouin scattering (SBS), an optical nonlinearity arising from photon-phonon interactions, has formed the basis for a large class of optical signal processing devices, including Brillouin amplifiers. A limiting factor of such…

We present first principles calculations of the phonon dispersions of Bi2Te3 and discuss these in relation to the acoustic phonon interface scattering in ceramics. The phonon dispersions show agreement with what is known from neutron…

Materials Science · Physics 2015-06-11 Xin Chen , David Parker , David J. Singh

We investigate the effects of electron and acoustic-phonon confinement on the low-field electron mobility of thin square silicon nanowires (SiNWs) that are surrounded by SiO$_2$ and gated. We employ a self-consistent…

Materials Science · Physics 2008-11-11 E. B. Ramayya , D. Vasileska , S. M. Goodnick , I. Knezevic

Optical nanofibers (ONFs) are excellent nanophotonic platforms for various applications such as optical sensing, quantum and nonlinear optics, due to both the tight optical confinement and their wide evanescent field in the sub-wavelength…

Silicon nanoparticles have the promise to surpass the theoretical efficiency limit of single-junction silicon photovoltaics by the creation of a "phonon bottleneck", a theorized slowing of the cooling rate of hot optical phonons that in…

Mesoscale and Nanoscale Physics · Physics 2021-04-14 Ilana J. Porter , Angela Lee , Scott K. Cushing , Hung-Tzu Chang , Justin C. Ondry , A. Paul Alivisatos , Stephen R. Leone

Stimulated Brillouin scattering was recently observed in nanoscale silicon waveguides. Surprisingly, thermally-driven photon-phonon conversion in these structures had not yet been reported. Here, we inject an optical probe in a suspended…

The incipient ferroelectric KTaO3 presents low-T Brillouin spectra anomalies,e.g. a broad central peak (CP), and some additional Brillouin doublets (BD), whose origin is interpreted in terms of phonon-density fluctuation processes. A…

Materials Science · Physics 2009-10-31 E. Farhi , A. K. Tagantsev , B. Hehlen , R. Currat , L. A. Boatner , E. Courtens

Low frequency acoustic vibration and phonon linewidth for CdTe0.68Se0.32 nanoparticle embedded in borosilicate glass are calculated using two different approaches by considering the elastic continuum model and fixed boundary condition. The…

Mesoscale and Nanoscale Physics · Physics 2009-04-16 Sanjeev K. Gupta , Prafulla K. Jha , A. K. Arora

We investigate from first-principles theory and experiment the generation of phonons on picosecond timescales and the relaxation of carriers in multiple conduction band valleys of photo-excited Ge by inter-valley electron-phonon scattering.…

Mesoscale and Nanoscale Physics · Physics 2025-02-03 F. Murphy-Armando , É. D. Murray , I. Savić , M. Trigo , D. Reis , S. Fahy

Spherical gold nanoclusters are grown by 1.8 MeV Au++ ion implantation into an amorphous silica matrix and subsequent air annealing at 873 K. Ultraviolet and visible light absorption confirms the presence of a dipolar surface plasmon peak…

Other Condensed Matter · Physics 2007-05-23 Daniel B. Murray , S. Dhara , T. R. Ravindran , K. G. M. Nair , S. Kalavathi , Lucien Saviot , Eugene Duval

We report lattice dynamical measurements, made using neutron inelastic scattering methods, of the relaxor perovskite PbMg1/3Nb2/3O3 (PMN) at momentum transfers near the edge of the Brillouin zone. Unusual"columns" of phonon scattering that…

Materials Science · Physics 2015-05-13 I. P. Swainson , C. Stock , P. M. Gehring , Guangyong Xu , K. Hirota , Y. Qiu , H. Luo , X. Zhao , J. -F. Li , D. Viehland

Nanoscale defects such as dislocations, have a significant impact on the phonon thermal transport properties in non-metallic materials. To unravel these effects, understanding of defect phonon modes is essential. Herein, at the atomic…

The elastic response of suspended NbSe3 nanowires is studied across the charge density wave phase transition. The nanoscale dimensions of the resonator lead to a large resonant frequency (10-100 MHz), bringing the excited phonon frequency…

We report a theoretical study of Stimulated Brillouin Scattering (SBS) in general anisotropic media, incorporating the effects of both acoustic strain and local rotation in all calculations. We apply our general theoretical framework to…

Optics · Physics 2019-03-27 M. J. A. Smith , C. Wolff , C. G. Poulton , C. M. de Sterke