On a biphononic origin of the 1125 cm^(-1) absorption band in cuprous oxide

TL;DR

This study uses IR spectroscopy to analyze the 1125 cm^{-1} absorption band in cuprous oxide, attributing it to a biphonon based on temperature dependence and vibrational analysis.

Contribution

It provides the first detailed spectroscopic evidence linking the 1125 cm^{-1} band to a biphonon in cuprous oxide.

Findings

The 1125 cm^{-1} band is assigned to a biphonon.

Temperature dependence supports the biphonon assignment.

IR and Raman spectra help identify vibrational modes.

Abstract

We report on the IR spectroscopic studies in both reflection (50-900 cm^{-1}) and transmission (900-3000 cm^{-1}) mode of the vibration spectrum of the cuprous oxide. A detailed analysis based on a comparison of the temperature dependences of the absorption band at 1125 cm^{-1} and of IR and Raman active fundamental vibrations results in assignment of the former to a biphonon.