Random lattice deformations in rare-earth-doped cubic hexafluoroelpasolites: High-resolution optical spectroscopy and theoretical studies

Deformation splittings in the spectra of LaAlO3: Ho3+, Pr3+, Tm3+single crystals

“…In particular, a well resolved splitting of RE spectral lines caused by random lattice strains was observed in the spectra of tetragonal centers in LiYF4:Tm 3+ [1] and CaWO4:Ho 3+ [3] crystals and of cubic centers in hexafluoroelpasolite crystals doped with Sm, Er, Tm, or Yb [2]. It is of interest to observe such effect in the spectra of trigonal centers, in which non-Kramers ions also possess doubly degenerate CF levels.…”

“…The work is devoted to a high-resolution spectroscopy study of the perovskite-type single crystals of LaAlO3 doped with non-Kramers rare-earth ions of praseodymium, holmium and thulium. Doublets of a specific shape were observed in the spectra, which we attribute to the presence of random deformations in the crystals.It has been shown earlier that for dielectric crystals doped with rare-earth (RE) ions random deformations of the crystal lattice may result in a specific shape (with a narrow dip in the center) of spectral lines corresponding to transitions between crystal-field (CF) singlets (or Kramers doublets) and non-Kramers doublets [1][2][3]. In particular, a well resolved splitting of RE spectral lines caused by random lattice strains was observed in the spectra of tetragonal centers in LiYF4:Tm 3+ [1] and CaWO4:Ho 3+ [3] crystals and of cubic centers in hexafluoroelpasolite crystals doped with Sm, Er, Tm, or Yb [2].…”

“…It has been shown earlier that for dielectric crystals doped with rare-earth (RE) ions random deformations of the crystal lattice may result in a specific shape (with a narrow dip in the center) of spectral lines corresponding to transitions between crystal-field (CF) singlets (or Kramers doublets) and non-Kramers doublets [1][2][3]. In particular, a well resolved splitting of RE spectral lines caused by random lattice strains was observed in the spectra of tetragonal centers in LiYF4:Tm 3+ [1] and CaWO4:Ho 3+ [3] crystals and of cubic centers in hexafluoroelpasolite crystals doped with Sm, Er, Tm, or Yb [2].…”

“…[1][2][3] enabled to successfully model the line shapes and gave a tool for getting a quantitative estimate for the concentration of intrinsic lattice defects, by comparing experimental and calculated spectral shapes. To perform such calculations, the CF and electron-deformation interaction parameters are necessary.…”

Phonon spectra of elpasolites Cs2NaRF6 (R=Y,Yb): Ab initio calculations

“…M 2 ALnX 6 crystals (A, M -metal, Ln-rare earth ion, X -halogen), with structure of an elpasolite (S.G. 225) attract attention of researchers as perspective optical matrixes [1,2,3,4,5].…”