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arXiv 0710.0215cond-mat.str-el
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三角格子哈伯德模型中磁阻挫的关联效应

Correlation effects on magnetic frustration in the triangular-lattice Hubbard model

Saptarshi Ghosh, Avinash Singh

摘要:

本文研究了三角格子哈伯德模型中磁响应函数的演化,在一个系统的反简并展开方案中引入了自能和顶点修正,并明确地保持了自旋-旋转对称性。结果表明,在半填充时,响应函数在中等耦合强度下在K点附近经历一个几乎无色散的区域,然后在强耦合下经历一个反演,导致在K点处的最大响应,与预期的120 ^o AF不稳定性一致。有限的空穴/电子掺杂的磁响应函数的影响也检查。

英文摘要:

Evolution of the magnetic response function in the triangular-lattice Hubbard model is studied with interaction strength within a systematic inverse-degeneracy expansion scheme which incorporates self-energy and vertex corrections and explicitly preserves the spin-rotation symmetry. It is shown that at half filling the response function goes through a nearly dispersionless regime around K for intermediate coupling strength, before undergoing an inversion at strong coupling, resulting in maximum response at the K point, consistent with the expected 120^o AF instability. Effects of finite hole/electron doping on the magnetic response function are also examined.

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