Physical review. B, Solid state
Thermodynamic properties of the dimerized half-filled-band Hubbard chain
U. Bernstein, Philip A. Pincus
Abstract
The dimerized-chain Hubbard model is characterized by a Coulomb energy $U$ and two alternating transfer constants, an intradimer constant $t$, and a smaller interdimer constant ${t}^{\ensuremath{'}}$. We have used thermodynamic perturbation theory to treat the half-filled-band case, taking the interdimer transfer as the perturbation term. The unperturbed problem is a lattice of isolated dimers. We give the energy, specific heat, and magnetic susceptibility as functions of temperature for the unperturbed case and for the first nonvanishing order in the perturbation. The results are consistent with the $U=0$ case, which is solved exactly. The interdimer transfer ${t}^{\ensuremath{'}}$ has the effect of distorting the peaks in the specific heat and reducing the susceptibility; this is shown graphically.