English
 
Help Privacy Policy Disclaimer
  Advanced SearchBrowse

Item

ITEM ACTIONSEXPORT

Released

Journal Article

Polaron and bipolaron defects in a charge density wave: A model for lightly doped BaBiO3

MPS-Authors
/persons/resource/persons261276

Bischofs,  IB       
Department of Physics and Astronomy, State University of New York, Stony Brook, New York, USA;
Theorie & Bio-Systeme, Max Planck Institute of Colloids and Interfaces, Max Planck Society;

External Resource
No external resources are shared
Fulltext (restricted access)
There are currently no full texts shared for your IP range.
Fulltext (public)
There are no public fulltexts stored in PuRe
Supplementary Material (public)
There is no public supplementary material available
Citation

Bischofs, I., Kostur, V., & Allen, P. (2002). Polaron and bipolaron defects in a charge density wave: A model for lightly doped BaBiO3. PHYSICAL REVIEW B, 65(11): 115112. doi:10.1103/PhysRevB.65.115112.


Cite as: https://hdl.handle.net/21.11116/0000-000C-91DE-6
Abstract
BaBiO3 is a prototype "charge ordering system'' forming interpenetrating sublattices with nominal valence Bi3+ and Bi5+. It can also be regarded as a three-dimensional version of a Peierls insulator, the insulating gap being a consequence of an ordered distortion of oxygen atoms. When holes are added to BaBiO3 by doping, it remains insulating until a very large hole concentration is reached, at which point it becomes superconducting. The mechanism for insulating behavior of more lightly doped samples is formation of small polarons or bipolarons. These are self-organized point defects in the Peierls order parameter, which trap carriers in bound states inside the Peierls gap. We calculate properties of the polarons and bipolarons using the Rice-Sneddon model. Bipolarons are the stable defect; the missing pair of electrons come from an empty midgap state built from the lower Peierls band. Each bipolaron distortion also pulls down six localized states below the bottom of the unoccupied upper Peierls band. The activation energy for bipolaron hopping is estimated.