Optical conductivity in multiferroic GaV${}_4$S${}_8$ and GeV${}_4$S${}_8$: Phonons and electronic transitions

S. Reschke, F. Mayr, Zhe Wang +7

We report on optical spectroscopy on the lacunar spinels GaV${}_4$S${}_8$ and GeV${}_4$S${}_8$ in the spectral range from 100 to 23000 cm${}^{-1}$ and for temperatures from 5 to 300 K. These…