Ground-state degeneracy and low-temperature thermodynamics of correlated electrons on highly frustrated lattices
✍ Scribed by A. Honecker; O. Derzhko; J. Richter
- Book ID
- 103887530
- Publisher
- Elsevier Science
- Year
- 2009
- Tongue
- English
- Weight
- 318 KB
- Volume
- 404
- Category
- Article
- ISSN
- 0921-4526
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✦ Synopsis
Highly frustrated lattices yield a completely flat lowest single-electron band. Remarkably, exact manybody ground states can be constructed for the repulsive Hubbard model and the t2J model by filling this flat band with localized electron states. This construction leads to a macroscopic ground-state degeneracy. We discuss how to compute these ground-state degeneracies for a certain class of models, including in particular the sawtooth chain. Furthermore, we discuss generic consequences for lowtemperature thermodynamic properties, like the appearance of a low-temperature peak in the specific heat. Finally, we present complementary numerical results obtained by exact diagonalization.