Revisiting longitudinal optical modes in materials with plasmon and plasmon-like absorptions -- SrTiO${}_3$ and $\beta$-Ga${}_2$O${}_3$

Thomas G. Mayerhöfer, Jürgen Popp

We investigate exemplary the longitudinal optical (LO) mode order in compounds with a plasmon or plasmon-like phonon mode and additional phonon modes. When the oscillator strength…