Y S Yang and C J Thompson 1991 J. Phys. A: Math. Gen. 24 L279 doi:10.1088/0305-4470/24/6/006
Y S Yang and C J Thompson
Show affiliationsHigh-temperature expansions for the specific heat and susceptibility of the strongly correlated Hubbard model are compared with corresponding quantities for spinless free fermions and free spins. It is found numerically that, when the temperature is high, the ratio of the specific heat of the strongly correlated Hubbard model to that of spinless free fermions approaches a particle-density-dependent constant. For fixed temperature, the susceptibility of the Hubbard model is less (greater) than that of free spins when the particle density is below (above) a certain threshold density of approximately 0.7. The ratio of the susceptibilities for the two systems, however, appears to be finite for any value of the particle density. Given that the free spin system does not have a ferromagnetic state at any finite temperature, it is concluded that the strongly correlated Hubbard model does not have a finite phase transition temperature. This conclusion is consistent with recent high-temperature expansion studies.
05.70.Ce Thermodynamic functions and equations of state
75.10.Lp Band and itinerant models
Issue 6 (21 March 1991)
Y S Yang and C J Thompson 1991 J. Phys. A: Math. Gen. 24 L279
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