Browsing by Author "Xu, J. H."
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- Hole dynamics and effective hole-hole interaction in a quantum antiferromagnetXu, J. H.; Ting, C. S.; Lee, T. K. (American Physical Society, 1991-04)By the use of an effective Hamiltonian which takes into account the constraint on the motion of holes in a quantum antiferromagnet, the dynamics of holes is investigated. It is found that there is a quasiparticle band whose width is of order J at the bottom of the hole spectrum. The effective hole-hole interaction mediated by spin fluctuations is derived and the attraction between holes in the d-wave channel is obtained. The results suggest that a d-wave-pairing condensation in a quantum antiferromagnet is very possible.
- Theoretical study of effective magnetic interactions in high-Tc Cu oxidesShen, J. L.; Xu, J. H.; Ting, C. S.; Lee, T. K. (American Physical Society, 1990-11)Starting from a two-band Hubbard model for cupric oxides and using perturbation theory, we study the effect of a small O-O hopping term tp on the parameters of the single-band t-J model. It is found that as long as the wave function on the oxygen site is extended and Bloch-like, the antiferromagnetic coupling between the nearest-neighbor copper spins decreases rapidly with increasing hole doping. This behavior seems to be insensitive to the value of tp and dispersion of the oxygen band, and is consistent with the results of recent experiments. We also show that between next-nearest-neighbor copper spins, there exists a non-negligible antiferromagnetic coupling even in the zero-doping limit.