Effect of electronic correlation on the shape of a large bipolaron: Four-lobed planar large bipolaron in an ionic medium
- Sandia National Laboratories, Albuquerque, New Mexico 87185-1421 (United States)
The shape of a large bipolaron is considered for self-trapped carriers confined within a plane that is immersed within a strongly ionic medium. For a wide enough electronic energy band, correlation effects determine a large bipolaron`s shape. Then a stable large bipolaron is found in which the two self-trapped carriers occupy mutually perpendicular dumbbell-shaped orbitals. This arrangement gives the self-trapped carriers a planar four-lobed charge density. With progressively narrower electronic bands, the short-range electron-lattice interactions become increasingly important. Then the stable solution shifts to that of a large bipolaron with a circularly symmetric shape. With a still narrower electronic band, the stable solution collapses to that of a small (single-site) bipolaron. Thus, there can be at least three types of stable planar bipolarons in an ionic medium: (1) a four-lobed large bipolaron, (2) a circularly symmetric large bipolaron, and (3) a small bipolaron. The forces between noncircularly symmetric bipolarons depend on their shapes and relative orientations. As a result, large bipolarons` shapes can affect how and if they order in their ground state.
- Research Organization:
- Sandia National Laboratory
- DOE Contract Number:
- AC04-94AL85000
- OSTI ID:
- 130711
- Journal Information:
- Physical Review, B: Condensed Matter, Journal Name: Physical Review, B: Condensed Matter Journal Issue: 19 Vol. 52; ISSN 0163-1829; ISSN PRBMDO
- Country of Publication:
- United States
- Language:
- English
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