Another approach to localized magnetic moments in the Hubbard model

Thereza Paiva, Carey Huscroft, Andrew K. McMahan +1 more

Anna Kauch, Krzysztof Byczuk

A. P. Kampf

We use a functional-integral representation for the Hubbard model to describe the formation of local moments and their magnetic correlations. In the absence of long-range magnetic order, the presence of well-established local moments alone is sufficient to produce a gap in the electronic spectrum. The local moments are treated within a coherent-potential approximation, and we apply an embedded-cluster method to incorporate their interactions.

Eleftherios N. Economou, P. M. Mihas

NIE HUI-QUAN, Guozhu Wei, Kaiyi Zhang +1 more

In this paper, using the local approach, we calculated the correlation energy, the local moments and the polarisation around the local moments in paramagnetic phase up to second order in the extended Hubbard model. It is shown that the polarisation is always antiferro-magnetic for different values of W. The correlation energy increases with W increasing for n = 1 and large U. The local moments and the antiferromagnetic polarisation decrease with W increasing for fixed n and U. While the effect of W on both the local moments and the antiferromagnetic polarisation is not obvious for small n or for large U and n = 1.

Zhi Hua Cheng, Yick Hong Chan, Jun Hui Liang +4 more