Pseudogap and the specific heat of high Tc superconductors: a Hubbard model in a n-pole approximation

International Conference on Strongly Correlated Electron Systems 2014

Calegari, E.J.^1 ; Lausmann, A.C.^1 ; Magalhaes, S.G.^2 ; Chaves, C.M.^3 ; Troper, A.^3

Laboratório de Teoria da Matéria Condensada, Departamento de Física-UFSM, Santa-Maria

97105-900, RS, Brazil^1

Instituto de Física, Universidade Federal Fluminense, Av. Litorânea s/n, Rio de Janeiro, Niterói

24210, 346, Brazil^2

Centro Brasileiro de Pesquisas Físicas, Rua Xavier Sigaud 150, Rio de Janeiro

22290-180, RJ, Brazil^3

关键词: Antiferromagnetics;    High Tc superconductors;    Nearest neighbors;    Pole approximation;    Pseudo-gap;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/592/1/012075/pdf
DOI  :  10.1088/1742-6596/592/1/012075

来源: IOP

【 摘 要 】

In this work the specific heat of a two-dimensional Hubbard model, suitable to discuss high-Tcsuperconductors (HTSC), is studied taking into account hopping to first (t) and second (t2) nearest neighbors. Experimental results for the specific heat of HTSC's, for instance, the YBCO and LSCO, indicate a close relation between the pseudogap and the specific heat. In the present work, we investigate the specific heat by the Green's function method within a n-pole approximation. The specific heat is calculated on the pseudogap and on the superconducting regions. In the present scenario, the pseudogap emerges when the antiferromagnetic (AF) fluctuations become sufficiently strong. The specific heat jump coefficient Δγ decreases when the total occupation per site (nT) reaches a given value. Such behavior of Δγ indicates the presence of a pseudogap in the regime of high occupation.