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arXiv · 0911.3596

Low-temperature properties of the Hubbard model on highly frustrated one-dimensional lattices

O. Derzhko·J. Richter·A. Honecker·M. Maksymenko·R. Moessner
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Abstract

We consider the repulsive Hubbard model on three highly frustrated one-dimensional lattices -- sawtooth chain and two kagomé chains -- with completely dispersionless (flat) lowest single-electron bands. We construct the complete manifold of {\em exact many-electron} ground states at low electron fillings and calculate the degeneracy of these states. As a result, we obtain closed-form expressions for low-temperature thermodynamic quantities around a particular value of the chemical potential $μ_0$. We discuss specific features of thermodynamic quantities of these ground-state ensembles such as residual entropy, an extra low-temperature peak in the specific heat, and the existence of ferromagnetism and paramagnetism. We confirm our analytical results by comparison with exact diagonalization data for finite systems.

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O. Derzhko, J. Richter, A. Honecker, M. Maksymenko, R. Moessner. 2009-11-18. Low-temperature properties of the Hubbard model on highly frustrated one-dimensional lattices. https://doi.org/10.1103/physrevb.81.014421

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