Resonance and antiresonance in Raman scattering in GaSe and InSe crystals

TL;DR

This study investigates how temperature influences Raman scattering in GaSe and InSe crystals, revealing resonant and antiresonant behaviors linked to energy proximity of optical transitions and electron-phonon interactions.

Contribution

It demonstrates temperature-dependent resonance and antiresonance phenomena in Raman scattering of GaSe and InSe, highlighting the role of electron-phonon coupling and quantum interference.

Findings

Resonance occurs at specific temperatures related to optical band gaps.

Antiresonance appears at higher temperatures following resonances.

Phonon mode intensities vary significantly with temperature.

Abstract

The temperature effect on the Raman scattering efficiency is investigated in $\varepsilon$-GaSe and $\gamma$-InSe crystals. We found that varying the temperature over a broad range from 5 K to 350 K permits to achieve both the resonant conditions and the antiresonance behaviour in Raman scattering of the studied materials. The resonant conditions of Raman scattering are observed at about 270 K under the 1.96 eV excitation for GaSe due to the energy proximity of the optical band gap. In the case of InSe, the resonant Raman spectra are apparent at about 50 K and 270 K under correspondingly the 2.41 eV and 2.54 eV excitations as a result of the energy proximity of the \mbox{so-called} B transition. Interestingly, the observed resonances for both materials are followed by an antiresonance behaviour noticeable at higher temperatures than the detected resonances. The significant variations of phonon-modes intensities can be explained in terms of electron-phonon coupling and quantum interference of contributions from different points of the Brillouin zone