A Temperature Study of High‐n$n$ Rydberg States in Cu2O${\rm Cu}_2{\rm O}$

Abstract

The temperature dependence of Rydberg excitons in with principal quantum numbers is investigated for bath temperatures between 1.3 and 50 K. The energy shift of Rydberg exciton lines allows us to perform a precise measurement of the band gap as a function of temperature. The phonon shows a dominant contribution to the temperature shift of the band gap. The optical properties of Rydberg excitons are analyzed for different temperatures and discussed in the context of phonon scattering as well as thermal ionization of impurities and compared to earlier descriptions in Ref. [1]. The maximum principal quantum number as a function of temperature in crystals of different quality is studied and compared. The observations are correlated to photoluminescence spectra of impurities at different temperatures.