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Free keywords:
high-temperature expansion; degeneracy; SU(n) symmetry; Heisenberg model; multipolar interaction
MPIPKS:
Strongly correlated electrons
Abstract:
Thermodynamic properties of the SU(n) Heisenberg model with the nearest-neighbor interaction in one dimension are studied by means of high-temperature expansion for arbitrary n. The specific heat up to 0[(betaJ)(23)] and the correlation function up to O[(betaJ)(19)] are derived with betaJ being the antiferromagnetic exchange in units of temperature. The series coefficients are obtained as explicit functions of n. It is found for n > 2 that the specific heat exhibits a shoulder on the high-temperature side of a peak. The origin of this structure is clarified by deriving the temperature dependence of the correlation function. With decreasing temperature, the short-range correlation with two-site periodicity develops first, and then another correlation occurs with n-site periodicity at lower temperature. This behavior is in contrast to that of the 1/r(2)-model, where the specific heat shows a single peak according to the exact solution.
