Low-temperature thermodynamics of one class of flat-band models

Abstract

We consider the antiferromagnetic Heisenberg model and the repulsive Hubbard model for a class of frustrated lattices with a completely dispersionless (flat) lowest one-particle (either one-magnon or one-electron) band. We construct exact many-particle ground states for a wide range of particle densities, calculate their degeneracy, and, as a result, obtain closed-form expressions for the low-temperature thermodynamic quantities around a particular value of the magnetic field $h_{\mathrm{sat}}$ or the chemical potential ${\mu }_0$. We confirm our analytic findings by numerical data for finite lattices.

4 pages including 3 PostScript files; to appear in Journal of Physics: Conference Series (proceedings of HFM2008)

References in corpus (7)

• Exact low-temperature behavior of kagome antiferromagnet at high fields
• Magnetocaloric effect in one-dimensional antiferromagnets
• Enhanced magnetocaloric effect in frustrated magnetic molecules with icosahedral symmetry
• Universal properties of highly frustrated quantum magnets in strong magnetic fields
• Linear independence of localized magnon states
• Low-temperature thermodynamics for a flat-band ferromagnet: Rigorous versus numerical results
• Enhanced low-temperature entropy and flat-band ferromagnetism in the t-J model on the sawtooth lattice