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Real-space pairing through charge transfer excitons in high-TC cuprates.
Michel Pouchard1, Jean-Pierre Doumerc, Antoine Villesuzanne
1CNRS, Université de Bordeaux, ICMCB, 87 Av. Dr. A. Schweitzer, Pessac, F-33608, France. pouchard@icmcb-bordeaux.cnrs.fr
Inorganic Chemistry
|December 9, 2008
Summary
Excitons form stabilizing interactions with doping holes in La(2)CuO(4) near a Mott-Hubbard transition. These exciton-solvated holes pair up and exhibit mobile, Bose-condensed behavior, driven by exciton-exciton interactions.
Area of Science:
- Condensed matter physics
- Materials science
- Quantum chemistry
Background:
- La(2)CuO(4) is a cuprate material exhibiting Mott-Hubbard transitions.
- Hole doping introduces charge carriers and can alter electronic properties.
- Excitons, bound electron-hole pairs, play a role in charge dynamics.
Purpose of the Study:
- To investigate the role of excitons in hole-doped La(2)CuO(4) approaching a Mott-Hubbard transition.
- To elucidate the nature of exciton-doping hole interactions and their consequences.
- To model the pairing and mobility of exciton-solvated doping holes.
Main Methods:
- Theoretical modeling of charge-transfer Frenkel excitons.
- Analysis of exciton-exciton and exciton-doping hole interactions.
- Consideration of charge carrier screening effects.
- Investigation of Bose condensation and pair gliding phenomena.
Main Results:
- Excitons are formed via stabilizing interactions with doping holes.
- Charge-transfer Frenkel excitons act as effective Cu(+)O(-) dipoles solvating doping charges.
- Mobile exciton-solvated doping holes form stable pairs.
- These pairs exhibit Bose condensation and glide in specific crystallographic directions.
Conclusions:
- Exciton-exciton dipolar interactions provide the pairing mechanism for doping holes.
- This model differs from previous excitonic theories by utilizing instantaneous interactions.
- The findings offer a new perspective on charge carrier behavior in Mott-Hubbard systems.
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