Физика Низких Температур: Том 31, Выпуск 8-9 (Август 2005), c. 995-1001    ( к оглавлению , назад )

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

Received January 13, 2005

Аннотация

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 -