Near-bandgap wavelength-dependent studies of long-lived traveling coherent longitudinal acoustic phonon oscillations in GaSb/GaAs systems

TL;DR

This study investigates long-lived coherent longitudinal acoustic phonon oscillations in GaSb/GaAs heterostructures using wavelength-dependent pump-probe measurements, revealing insights into the optical properties and phonon dynamics at the interface.

Contribution

First experimental observation of long-lived traveling coherent phonons in GaSb/GaAs systems, linking phonon behavior to optical properties near the bandgap.

Findings

Oscillations originate from coherent phonons traveling across the interface.

Wavelength dependence correlates with optical properties of GaAs.

Provides new insights into phonon dynamics in heterostructures.

Abstract

We report first studies of long-lived oscillations in optical pump-probe measurements on GaSb-GaAs heterostructures. The oscillations arise from a photogenerated coherent longitudinal acoustic phonon wave, which travels from the top surface of GaSb across the interface into the GaAs substrate, providing information on the optical properties of the material as a function of time/depth. Wavelength-dependent studies of the oscillations near the bandgap of GaAs indicate strong correlations to the optical properties of GaAs.