EFFECT OF THE 3-SITE HOPPING TERM ON THE T-J MODEL

被引:34
作者
AMMON, B [1 ]
TROYER, M [1 ]
TSUNETSUGU, H [1 ]
机构
[1] ETH ZURICH, CH-8093 ZURICH, SWITZERLAND
来源
PHYSICAL REVIEW B | 1995年 / 52卷 / 01期
关键词
D O I
10.1103/PhysRevB.52.629
中图分类号
T [工业技术];
学科分类号
08 ;
摘要
We have used exact diagonalization and quantum Monte Carlo methods to study the one-dimensional t-J model including the three-site hopping term derived from the strong-coupling limit of the Hubbard model. The three-site term may be important to superconducting correlations since it allows direct hopping of local singlet electron pairs. The phase diagram is determined for several values of the strength of the three-site term and compared with that of the t-J and Hubbard models. Phase separation, which exists in the t-J model, is suppressed. In the low electron density region the formation of local singlet electron pairs is enhanced, leading to stronger superconducting correlations even for values J/t<2. A large spin gap region extends from low electron densities up to high densities. In the low hole density region the superconducting correlations are suppressed at J/t>2.8 in spite of enhanced pair formation. This is because the three-site term, while enhancing the formation of electron pairs, leads to a repulsion between holes. © 1995 The American Physical Society.
引用
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页码:629 / 636
页数:8
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