Long-lived optical phonons in ZnO studied with impulsive stimulated Raman scattering

TL;DR

This study measures the anharmonic properties of low-frequency E2 phonons in ZnO using impulsive stimulated Raman scattering, revealing long lifetimes and potential applications in quantum technologies and materials characterization.

Contribution

It provides precise measurements of phonon frequency and lifetime in ZnO, highlighting the impact of isotopic disorder on phonon lifetime and suggesting improvements with isotopically-pure samples.

Findings

Phonon lifetime at 5 K is approximately 211 ps.

Long phonon lifetime suggests applications in quantum computation.

Isotopic purity could extend phonon lifetime to nanoseconds.

Abstract

The anharmonic properties of the low-frequency E2 phonon in ZnO were measured using impulsive stimulated Raman scattering. At 5 K, the frequency and lifetime are (2.9787 +/- 0.0002) THz and (211 +/- 7) ps. The unusually long lifetime and the high accuracy in the determination of the frequency hold promise for applications in metrology, quantum computation and materials characterization. The temperature dependence of the lifetime is determined by two-phonon up-conversion decay contributions, which vanish at zero temperature. Results suggest that the lifetime is limited by isotopic disorder and that values in the nanosecond range may be achievable in isotopically-pure samples.