Protonic conductivity at the superionic phase transitions in the M3H(XO4)(2) crystal group

Authors
Citation
Ni. Pavlenko, Protonic conductivity at the superionic phase transitions in the M3H(XO4)(2) crystal group, J PHYS-COND, 11(26), 1999, pp. 5099-5110
Citations number
17
Categorie Soggetti
Apllied Physucs/Condensed Matter/Materiales Science
Journal title
JOURNAL OF PHYSICS-CONDENSED MATTER
ISSN journal
09538984 → ACNP
Volume
11
Issue
26
Year of publication
1999
Pages
5099 - 5110
Database
ISI
SICI code
0953-8984(19990705)11:26<5099:PCATSP>2.0.ZU;2-6
Abstract
A microscopic model for the description of the proton subsystem dynamics in superionic crystals with hydrogen bonds is developed. Besides the inclusio n of the proton-transport mechanism, the effect of the displacement of the nearest oxygens during hydrogen-bond formation is taken into account. The l atter effect is the cause of the strong proton-phonon coupling that leads t o the polaronic effect. Using the occupation number formalism, the virtual (in superionic phases) or ordered (in low-temperature phases) character of the hydrogen-bonded system is taken into account on the basis of the proton -ordering model. Protonic conductivity studies are carried out in the frame work of the Kubo theory for the cases of superionic phases as well as low-t emperature phases with different types of proton ordering (as an example th e M3H(XO4)(2) class of crystals is considered). The temperature dependencie s of the conductivity are analysed. The activation energies for the static conductivity are determined; for this case the influence of the internal fi eld which appears as a result of the proton ordering is investigated.