Charge Disproportionation and Superconductivity in Tl- and In-doped Lead Telluride
Journal article, 2012
The "negative-U model" is analyzed and applied to Tl- and In-doped lead telluride, Pb1-x Tl (x) Te, and Pb1-x In (x) Te, respectively. The former, but not the latter, is superconducting (T (c)< 1.5 K) in a certain concentration range (x (c)> 0.003). At very low concentrations, carriers are created in the valence band and the conductivity is metallic, of the ordinary kind. Matsushita et al. and Erickson et al. explain this as due to disproportionation 2Tl(2+)-> Tl+ and Tl3+. The latter authors are of the opinion that indium also disproportionates in the same way as thallium. If this would be the case, it would be hard to explain the absence of superconductivity at indium doping. In this paper it is shown that In2+ does not disproportionate under the given circumstances. The Hubbard model, extended and generalized, is therefore consistent with all experimental results.
solid-solutions
polaron motion
Superconductivity
impurities
pbte
states
transport
PbTe
model
electronic-structure
Hubbard-U
Thallium
Madelung
Author
Sven Larsson
Chalmers, Chemical and Biological Engineering, Physical Chemistry
Journal of Superconductivity and Novel Magnetism
1557-1939 (ISSN) 1557-1947 (eISSN)
Vol. 25 2 319-323Subject Categories
Chemical Sciences
DOI
10.1007/s10948-011-1309-z