منابع مشابه
Ultrafast relaxation dynamics of hot optical phonons in graphene
Using ultrafast optical pump-probe spectroscopy, we study the relaxation dynamics of hot optical phonons in few-layer and multilayer graphene films grown by epitaxy on silicon carbide substrates and by chemical vapor deposition on nickel substrates. In the first few hundred femtoseconds after photoexcitation, the hot carriers lose most of their energy to the generation of hot optical phonons wh...
متن کاملNon-thermal hot electrons ultrafastly generating hot optical phonons in graphite
Investigation of the non-equilibrium dynamics after an impulsive impact provides insights into couplings among various excitations. A two-temperature model (TTM) is often a starting point to understand the coupled dynamics of electrons and lattice vibrations: the optical pulse primarily raises the electronic temperature T(el) while leaving the lattice temperature T(l) low; subsequently the hot ...
متن کاملCoherent Excitation of Optical Phonons in GaAs by Broadband Terahertz Pulses
Coherent excitation and control of lattice motion by electromagnetic radiation in optical frequency range has been reported through variety of indirect interaction mechanisms with phonon modes. However, coherent phonon excitation by direct interaction of electromagnetic radiation and nuclei has not been demonstrated experimentally in terahertz (THz) frequency range mainly due to the lack of THz...
متن کاملOptical phonons in isotope superlattices of GaAs, GaP, and GaSb studied by Raman scattering
We have investigated the LO-phonon Raman spectra of @100# oriented gallium isotope superlattices (GaX)n( GaX)n @X5P,As; both elements have a single stable isotope# at low temperature. When the number of monolayers 2n within one superlattice ~SL! unit cell is varied, anticrossings between phonons confined in the GaX and GaX layers are observed. We have used a planar bond-charge model to calculat...
متن کاملMechanisms for the generation of coherent longitudinal-optical phonons in GaAs /AlGaAs multiple quantum wells.
We show that coherent optical phonons in GaAs multiple quantum wells are generated in a completely different way as compared to bulk GaAs. Unlike in bulk GaAs where the ultrafast screening of electric fields by photogenerated charge carriers is known to be dominant, three distinctive generation mechanisms contribute simultaneously in multiple quantum wells. The interplay between impulsive Raman...
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ژورنال
عنوان ژورنال: Physica B+C
سال: 1983
ISSN: 0378-4363
DOI: 10.1016/0378-4363(83)90537-5