Resonance and antiresonance in Raman scattering in GaSe and InSe crystals

The temperature effect on the Raman scattering efficiency is investigated in epsilon-GaSe and gamma-InSe crystals. We found that varying the temperature over a broad range from 5 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 and 270 K under correspondingly the 2.41 eV and 2.54 eV excitations as a result of the energy proximity of the 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.

Automated summary

The temperature effect on the Raman scattering efficiency in epsilon-GaSe and gamma-InSe crystals was investigated, revealing resonant conditions and antiresonance behavior. Resonant Raman spectra were observed at specific temperatures due to energy proximity of optical band gaps, accompanied by antiresonance behavior at higher temperatures. The variations in phonon-modes intensities were explained by electron-phonon coupling and quantum interference from different points of the Brillouin zone.