Acoustic interference in random superlattices

Surface acoustic waves in Ni/V superlattices.

%e have measured the surface-acoustic-wave velocities in Ni/V superlattices using both Brillouin scattering and surface-acoustic-wave techniques; the results are in good quantitative agreement. These results confirm earlier reports of phonon-velocity softening in bcc/fcc superlattices and prove that this is a general phenomenon, not a consequence of the measurement method. In addition, we descr...

Quasi-ballistic-electron transport in random superlattices.

We theoretically study electron transport in disordered, quantum-well based, semiconductor superlattices with structural short-range correlations. Our system consists of equal width square barriers and quantum wells with two different thicknesses. The two kinds of quantum wells are randomly distributed along the growth direction. Structural correlations are introduced by adding the constraint t...

Raman Scattering by Acoustic Phonons and Structural Properties of Fibonacci, Thue-morse and Random Superlattices

Coherent control of acoustic phonons in semiconductor superlattices

Coherent acoustic phonons are generated in GaAs/AlAs superlattices by excitation with femtosecond laser pulses. Several modes of the acoustic phonon spectrum are observed, in agreement with the effect of zone folding in the mini-Brillouin zone of the superlattice. By applying successive pump pulses we are able to silence the first back-folded mode near q50, while selectively enhancing the coher...

Progress towards terahertz acoustic phonon generation in doping superlattices

Progress is described in experiments to generate coherent terahertz acoustic phonons in silicon doping superlattices by the resonant absorption of nanosecond-pulsed far-infrared laser radiation. Future experiments are proposed that would use the superlattice as a transducer in a terahertz cryogenic acoustic reflection microscope with sub-nanometer resolution.