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arXiv · 1305.3210

Specific heat of a non-local attractive Hubbard model

E. J. Calegari·C. O. Lobo·S. G. Magalhaes·C. M. Chaves·A. Troper
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Abstract

The specific heat of an attractive (interaction $G<0$) non-local Hubbard model is investigated. We use a two-pole approximation which leads to a set of correlation functions. In particular, the correlation function $\ <\vec{S}_i\cdot\vec{S}_j\ >$ plays an important role as a source of anomalies in the normal state of the model. Our results show that for a giving range of $G$ and $\delta$ where $\delta=1-n_T$ ($n_T=n_{\uparrow}+n_{\downarrow}$), the specific heat as a function of the temperature presents a two peak structure. Nevertehelesss, the presence of a pseudogap on the anti-nodal points $(0,\pm\pi)$ and $(\pm\pi,0)$ eliminates the two peak structure, the low temperature peak remaining. The effects of the second nearest neighbor hopping on the specific heat are also investigated.

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E. J. Calegari, C. O. Lobo, S. G. Magalhaes, C. M. Chaves, A. Troper. 2013-05-14. Specific heat of a non-local attractive Hubbard model. https://doi.org/10.1016/j.physleta.2013.04.041

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