Low-temperature thermodynamics of one class of flat-band models
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 $h_{\rm{sat}}$ or the chemical potential $μ_0$. We confirm our analytic findings by numerical data for finite lattices.
cond-mat.str-el↗