Electronic structure and energy level schemes of RE3+

Autor(en)

Ismail A. M. Ibrahim, Zoltan Lences, Pavol Sajgalik, Lubomir Benco

Abstrakt

First principles calculations of rare earth (RE)-doped LaSi3N5 host lattice are performed to obtain the electronic structure, the band gap (BG), and the character of electronic transitions. Doping with both trivalent and bivalent RE cations is inspected. RE 4f states form two bands of occupied and unoccupied states separated by ~5 eV. In RE3+-doped compounds 4f states are shifted by ~6 eV to more negative energies compared with RE2+-compounds. This stabilization causes that RE3+ 4f bands are in a different position relative to the valence band and the conduction band than RE2+ 4f bands and therefore different electronic transitions apply. BG of RE3+-compounds decreases from ~4.6 eV (Ce) to ~1.5 eV (Eu). Except for Ce3+, exhibiting the 4f→5d transition, other RE3+-compounds show the charge transfer of the p→4f character. BG of RE2+-compounds increases from ~0.80 eV (Ce, Pr) to ~0.95 eV (Nd, Pm), ~1.43 eV (Sm), and ~3.28 eV (Eu) and the electronic transition is of the 4f→5d character. The energy level scheme constructed from ab initio calculated electronic structures agrees well with the experimental energy level diagram. The agreement demonstrates the reliability of the hybrid functional HSE06 to describe correctly bands of nonbonding RE 4f electrons.

Organisation(en)

Computergestützte Materialphysik

Externe Organisation(en)

Slovak Academy of Sciences (SAS)

Journal

Journal of Luminescence

Band

164

Seiten

131-137

Anzahl der Seiten

7

ISSN

0022-2313

DOI

https://doi.org/10.1016/j.jlumin.2015.03.035

Publikationsdatum

08-2015

Peer-reviewed

Ja

ÖFOS 2012

103025 Quantenmechanik, 103036 Theoretische Physik, 103015 Kondensierte Materie, 103009 Festkörperphysik

Schlagwörter

ASJC Scopus Sachgebiete

Condensed Matter Physics, Atomic and Molecular Physics, and Optics, Allgemeine Chemie, Biophysics, Biochemistry

Link zum Portal

https://ucrisportal.univie.ac.at/de/publications/0f758593-c4fe-4059-bfb7-551b9cd76f5c