TY  - JOUR
AU  - Kudryavtseva, I.
AU  - Klopov, M.
AU  - Lushchik, A.
AU  - Lushchik, Ch
AU  - Maaroos, A.
AU  - Pishtshev, A.
TI  - Electronic excitations and self-trapping of electrons and holes in CaSO<sub>4</sub>
JO  - Physica scripta
VL  - 89
IS  - 4
SN  - 1402-4896
CY  - Bristol
PB  - IoP Publ.
M1  - PUBDB-2015-01929
SP  - 044013
PY  - 2014
AB  - A first-principles study of the electronic properties of a CaSO4 anhydrite structural phase has been performed. A theoretical estimation for the fundamental band gap (p → s transitions) is Eg = 9.6 eV and a proper threshold for p → d transitions is Epd = 10.8 eV. These values agree with the data obtained for a set of CaSO4 doped with Gd3+, Dy3+, Tm3+ and Tb3+ ions using the methods of low-temperature highly sensitive luminescence and thermoactivation spectroscopy. The results are consistent with theoretical predictions of a possible low-temperature self-trapping of oxygen p-holes. The hopping diffusion of hole polarons starts above  40 K and is accompanied by a  50–60 K peak of thermally stimulated luminescence of RE3+ ions caused due to the recombination of hole polarons with the electrons localized at RE3+. There is no direct evidence of the self-trapping of heavy d-electrons, however, one can argue that their motion rather differs from that of conduction s-electrons.
LB  - PUB:(DE-HGF)16
UR  - <Go to ISI:>//WOS:000333449400014
DO  - DOI:10.1088/0031-8949/89/4/044013
UR  - https://bib-pubdb1.desy.de/record/208877
ER  -