Energy transfer from the translational degrees of freedom to phonon modes is studied for isolated systems of two coaxial carbon nanotubes, which may serve as a nearly frictionless nano-oscillator. It is found that for oscillators with short nanotubes (less than 30 A) a rocking motion, occurring when the inner tube is pulled about 1/3 out of the outer tube, is responsible for significant phonon ...

An electromechanical resonator harboring an atomlike spectrum of discrete mechanical vibrations, namely, phonon modes, has been developed. A purely mechanical three-mode system becomes available in the electromechanical atom in which the energy difference of the two higher modes is resonant with a long-lived lower mode. Our measurements reveal that even an incoherent input into the higher mode ...

The suppression of transverse phonons by liquidlike diffusion in superionic conductors has been proposed as a means to dramatically reduce thermal conductivity in thermoelectric materials [H. Lui et al. Nat. Mater. 11, 422 (2012)NMAACR1476-112210.1038/nmat3273]. We have measured the ion transport and lattice dynamics in the original phonon-liquid electron-crystal Cu_{2}Se using neutron spectros...

It is shown that Förster's expression for the electronic energy transfer rate can be recast in a form predicted for exciton motion that interacts strongly with molecular vibrations. Using a simple model based on the Kennard-Stepanov theory, Förster's expression for the spectral overlap is shown to be of a thermally activated form, as obtained previously by multiphonon theory. In contrast, the h...

Phonons – quanta of crystal lattice vibrations – reveal themselves in all electrical, thermal and optical phenomena in materials. Nanostructures open exciting opportunities for tuning the phonon energy spectrum and related properties of materials for specific applications. A recent advent of graphene and quasi two-dimensional materials increased the possibilities for controlled modification of ...

We report the observation of coherent lattice vibrations in mono- and few-layer WSe2 in the time domain, which were obtained by performing time-resolved transmission measurements. Upon the excitation of ultrashort pulses with the energy resonant to that of A excitons, coherent oscillations of the A1g optical phonon and longitudinal acoustic phonon at the M point of the Brillouin zone (LA(M)) we...

Phonons, i.e., quanta of lattice vibrations, manifest themselves practically in all electrical, thermal, optical, and noise phenomena in semiconductors and other material systems. Reduction of the size of electronic devices below the acoustic phonon mean free path creates a new situation for the phonons propagation and interaction. From one side, it may complicate heat removal from the downscal...

The existence of multiphonon states in the nuclear spectrum of excitation has been predicted since the introduction of collective models [1]. Examples of low-lying nuclear vibrational states have been known for many years in nuclear spectra and are still being actively investigated with new generation of detectors; in particular, two-phonon multiplets and some three-phonon states based on the l...

Recently, we reported high resolution angle-resolved photoemission measurements that indicated unusually strong coupling between adsorbate vibrations and a surface-localized electron state in the system W(110)-(131)H. We have now extended these measurements to probe the electron–phonon coupling strength as a function of position on the relevant Fermi contour. We find that the strength of the co...