Single Band Hubbard Model with Infinite Repulsion on 2×2×2 Lattice

抄録

All the energy eigenvalues of the Hubbard model with infinite repulsion on 2×2×2 cubic lattice for different electron numbers N_e are calculated numerically. For N_e=4, 7 the ground state is completely ferromagnetic; namely, total spin S is N_e⁄2. For N_e=5, the total spin of the ground state is 3/2. For N_e=2, 6, it is zero. For N_e=1, 3, it is 1/2. Thermodynamic quantities such as entropy, susceptibility and specific heat are calculated with the method of canonical ensemble. There are two peaks in the specific heat curve for N_e=4, 5, 6, 7, but only one peak for N_e=1, 2, 3.