标题： 熵和二维t-J模型的热电功率 显示英文标题

标题： Entropy and thermopower in the 2D t-J model

摘要： 二维$t$-$J$模型的熵通过其12阶高温级数进行研究。 对熵级数的直接Padé外推在低于$T\sim J$的温度下收敛效果不佳。 级数系数是精确的多项式，因此通过修改被外推的级数可以改善级数的收敛性。 通过从$t$-$J$熵级数中减去海森堡反铁磁体熵的缩放版本，低温收敛性得到显著改善。 使用这种技术得到了电子密度和温度的全范围结果。 电子密度是级数系数中的可调参数，使得可以在固定温度$\partial S/\partial n|_T$下准确确定熵的密度依赖性和密度导数。 密度导数强烈依赖于温度，这与非相互作用模型不同。 密度导数也是实验测量的热电势的近似值。 显示英文摘要

摘要： The entropy of the two-dimensional $t$-$J$ model is investigated using its 12th order high temperature series. A direct Pad\'{e} extrapolation of the entropy series doesn't converge well for temperatures below $T\sim J$. The series coefficients are exact polynomials so the series convergence can be improved by modifying the series that is extrapolated. By subtracting a scaled version of the series for the entropy of the Heisenberg antiferromagnet from the $t$-$J$ entropy series the low temperature convergence is greatly improved. Using this technique results are obtained for the full range of electron densities and temperatures. The electron density is an adjustable parameter in the series coefficients allowing the density dependence of the entropy and the density derivative at fixed temperature $\partial S/\partial n|_T$ to be determined accurately. The density derivative depends strongly on temperature, unlike noninteracting models. The density derivative is also an approximation to the experimentally measured thermopower.