相关论文: Anharmonic Decay of Coherent Optical Phonons in An…
Femtosecond dynamics of coherent optical phonons in GeTe/Sb$_{2}$Te$_{3}$ superlattices (SLs), a new class of semiconductor SLs with three different states, have been investigated by using a reflection-type pump-probe technique at various…
The femtosecond optical pump-probe technique was used to study dynamics of photoexcited electrons and coherent optical phonons in transition metals Zn and Cd as a function of temperature and excitation level. The optical response in time…
We report on the temperature dependence of the anharmonic decay rate of zone-center (G mode) optical phonons in both single-walled carbon nanotubes and graphite. The measurements are performed using a pump-probe Raman scattering scheme with…
We observe anharmonic decay of the photoexcited coherent A1g phonon in bismuth to points in the Brillouin zone where conservation of momentum and energy are satisfied for three-phonon scattering. The decay of a coherent phonon can be…
Time-resolved Raman spectroscopy has been applied to probe the anharmonic coupling and electron-phonon interaction of optical phonons in graphite. From the decay of the transient anti-Stokes scattering of the G-mode following ultrafast…
The anharmonic contribution to phonon lifetime and its temperature dependence is calculated from first principle in C, Si and Ge using third-order density-functional perturbation theory. Good agreement with available experimental data is…
Phonon decoherence determines the characteristic timescales over which coherent lattice vibrations decay, making it a crucial process for understanding the non-equilibrium dynamics of crystal lattices after excitation by a pump pulse. Here,…
We investigate ultrafast phonon dynamics in the Bi$_{1-x}$Sb$_{x}$ alloy system for various compositions $x$ using a reflective femtosecond pump-probe technique. The coherent optical phonons corresponding to the A$_{1g}$ local vibrational…
We examine anharmonic contributions to the optical phonon modes in bulk $T_d$-MoTe$_2$ through temperature-dependent Raman spectroscopy. At temperatures ranging from 100 K to 200 K, we find that all modes redshift linearly with temperature…
We investigate the excitation of phonons in photoexcited antimony and demonstrate that the entire electron-lattice interactions, in particular coherent and incoherent electron-phonon coupling, can be probed simultaneously. Using femtosecond…
Anharmonic lattice vibrations play a key role in many physical phenomena. They govern the heat conductivity of solids, strongly affect the phonon spectra, play a prominent role in soft mode phase transitions, allow ultrafast engineering of…
We have investigated the dynamical properties of coherent phonons generated in antimony under high density photo excitation. Precise measurements and extended analysis of coherent phonon oscillations provide new insights into the process of…
We report inelastic light scattering experiments on CaFe_2As_2 in the temperature range of 4 to 290 K. In in-plane polarizations two Raman-active phonon modes are observed at 189 and 211 cm-1, displaying A_1g and B_1g symmetries,…
Anharmonic effects in an atomic monolayer thin crystal with honeycomb lattice structure are investigated by analytical and numerical lattice dynamical methods. Starting from a semi-empirical model for anharmonic couplings of third and…
We investigate coherent phonon oscillations of BaFe$_2$As$_2$ using optical pump-probe spectroscopy. Time-resolved optical reflectivity shows periodic modulations due to $A_{1g}$ coherent phonon of $c$-axis arsenic vibrations. Optical probe…
We study the relaxation of coherent acoustic phonon modes with frequencies up to 500 GHz in ultra-thin free-standing silicon membranes. Using an ultrafast pump-probe technique of asynchronous optical sampling, we observe that the decay time…
We directly measure by femtosecond time-resolved x-ray diffraction the E$_g$ symmetry coherent phonon excited in bismuth by strong optical excitation. The magnitude of the E$_g$ mode observed is 0.2 pm peak-to-peak, compared against the 2.7…
The two-phonon decay of self-localized soliton in a one-dimensional monatomic anharmonic lattice caused by cubic anharmonicity is considered. It is shown that the decay takes place with emission of phonon bursts. The average rate of…
A nonperturbative theory of multiphonon anharmonic decay of strongly excited local mode is developed whereby the mode is considered classically and phonons, quantum mechanically. The decay rate of the mode is expressed via the negative…
High-harmonic generation in solids has emerged as a powerful probe of ultrafast electron dynamics and lattice motion, and recent theoretical work has suggested that thermally driven lattice fluctuations can act as an effective source of…