Excitons and rare-earth ions in CsCdBr3

Heber J., Demirbilek R., Nikitin S.

JOURNAL OF ALLOYS AND COMPOUNDS, vol.380, pp.50-54, 2004 (SCI-Expanded) identifier identifier

  • Publication Type: Article / Article
  • Volume: 380
  • Publication Date: 2004
  • Doi Number: 10.1016/j.jallcom.2004.03.021
  • Journal Name: JOURNAL OF ALLOYS AND COMPOUNDS
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Page Numbers: pp.50-54
  • Yıldız Technical University Affiliated: No

Abstract

CsCdBr3 has a quasi-linear crystal structure. It consists of covalently bound [CdBr](6)(4-) chains separated by chains of Cs+ ions. The trivalent rare-earth (RE) ions substitute for divalent Cd ions forming predominantly pair centers of the type RE3+-(Cd vacancy)-RE3+. A minority of RE ions forms "single-ion" centers with more distant charge compensation. The electronic structure around the band gap is determined by the [CdBr](6)(4-) octahedra. The lowest excitonic states of the lattice are charge-transfer states of these octahedra. At low temperatures they form self-trapped excitons which become mobile around 80 K.