Fizika Nizkikh Temperatur: Volume 31, Number 8-9 (August 2005), p. 995-1001    ( to contents , go back )

Antiferromagnetism and superconductivity of the two-dimensional extended t-J model

C.T. Shih1, J.J. Wu1, Y.C. Chen1, C.Y. Mou2, C.P. Chou2, R. Eder3, and T.K. Lee4

1Department of Physics, Tunghai University, Taichung, Taiwan
E-mail: ctshih@mail.thu.edu.tw

2Department of Physics, National Tsing Hua University, Hsinchu, Taiwan

3Institut für Festkörperphysik, Forschungszentrum Karlsruhe, Germany

4Institute of Physics, Academia Sinica, Nankang, Taiwan
pos Анотація:

Received January 13, 2005

Abstract

The mechanism of high-temperature superconductivity (HTS) and the correlation between the antiferromagnetic long-range order (AFLRO) and superconductivity (SC) phases are the central issues of the study of HTS theory. SC and AFLRO of the hole-doped two-dimensional extended t- J model are studied by the variational Monte Carlo method. The results show that SC is greatly enhanced by the long-range hopping terms t' and t" for the optimal and overdoped cases. The phase of coexisting SC and AFM in the t-J model disappears when t and t" are included. It is concluded that the extended t-J model provides a more accurate description for HTS than the traditional t-J model does. The momentum distribution function n(k) and the shape of Fermi surface play critical roles for establishing the phase diagram of HTS materials.

PACS:
74.20.-z - Theories and models of superconducting state
74.25.Ha - Magnetic properties
71.18+y -
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