Pair breaking in semiclassical singlet small-bipolaron hopping

Journal Article · Mon Jan 01 04:00:00 EST 1996 · Physical Review, B: Condensed Matter

DOI:https://doi.org/10.1103/PhysRevB.53.1260· OSTI ID:278528

Emin, D ^[1]

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1. Sandia National Laboratories, Albuquerque, New Mexico 87185-1421 (United States)

The Holstein-Hubbard model is used to study high-temperature ({ital T}{approx_gt}{ital T}{sub phonon}/3) hopping transport when it is energetically favorable for carriers to pair as singlet small bipolarons. The semiclassical rates for one-electron transfers involving small polarons are found to be much greater than those that only involve small bipolarons. In particular, the most rapid one-electron-transfer processes have a small-polaron hopping to a vacant site and one of a small bipolaron{close_quote}s two carriers jumping onto the site of an adjacent small polaron. As a result, even when most carriers form small bipolarons rather than small polarons, one-electron transfers involving small polarons always dominate the dc conductivity. The energy to thermally generate small polarons from small bipolarons thus contributes to the conductivity{close_quote}s activation energy. This pair-breaking energy also manifests itself in a thermally activated contribution to the system{close_quote}s paramagnetic susceptibility. In addition, the carriers{close_quote} Seebeck coefficient garners a contribution with a temperature dependence that is characterized by the pair-breaking energy. {copyright} {ital 1996 The American Physical Society.}

• Research Organization: Sandia National Laboratory
• DOE Contract Number: AC04-94AL85000
• OSTI ID: 278528
• Journal Information: Physical Review, B: Condensed Matter, Journal Name: Physical Review, B: Condensed Matter Journal Issue: 3 Vol. 53; ISSN PRBMDO; ISSN 0163-1829
• Country of Publication: United States
• Language: English

Related Subjects

66 PHYSICS
ACTIVATION ENERGY
CHARGE CARRIERS
ELECTRIC CONDUCTIVITY
HOPPING
MAGNETIC SUSCEPTIBILITY
PAIRING INTERACTIONS
POLARONS
SEEBECK EFFECT
SEMICLASSICAL APPROXIMATION
TEMPERATURE DEPENDENCE