Oliver Ristow

TL;DR: The experimental results are compared with theories considering both intrinsic phonon-phonon interactions and extrinsic surface roughness scattering including a wavelength-dependent specularity to understand some of the limits of nanomechanical resonators and thermal transport in nanostructures.

TL;DR: In this article, the authors studied the relaxation of coherent acoustic phonon modes with frequencies up to 500 GHz in ultrathin free-standing silicon membranes and observed that the decay time of the first-order dilatational mode decreases significantly from 4: 7n sto 5 ps with decreasing membrane thickness from � 194 to 8 nm.

TL;DR: In this paper, Rayleigh and leaky longitudinal surface acoustic wave modes are detected in the time domain for various propagation distances by measuring on various pitches and comparing the spectra with finite element calculations.

TL;DR: The experiments and theoretical analysis indicate for the first time that the molecular nano-layers are much more viscous than elastic in the investigated frequency range from 50 to 120 GHz and thus show pronounced acoustic absorption.

TL;DR: In this article, the damping time of coherent longitudinal vibrations of a thin gold film and a silicon substrate was investigated by ultrafast pump-probe spectroscopy providing quantitative values on the dampness of the gold film.