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arXiv 0711.1990cond-mat.str-el
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一维Wigner晶格的磁性及其对电荷序的影响

Magnetism of one-dimensional Wigner lattices and its impact on charge order

M. Daghofer, R. M. Noack, P. Horsch

摘要:

本文研究了四分之一填充的具有最近邻和次最近邻跳跃t_1和t_2的广义Wigner晶格的磁相图。我们发现一个区域在负t_2与完全饱和的铁磁基态,我们归因于动力学交换。这种相互作用在t_2 <0时不利于反铁磁性的产生,它是由Wigner晶格的电荷能隙中的虚激发引起的,而Wigner晶格的电荷能隙远小于与U成正比的Mott-Hubbard能隙。值得注意的是,我们发现一个很强的依赖性的电荷结构因子的磁性,即使在限制U到无穷大,相反的期望,在维格纳晶格制度中的电荷排序应该很好地描述了无自旋费米子。我们的结果,得到使用密度矩阵重整化群和精确对角化,可以通过一个有效的低能哈密顿透明地解释。

英文摘要:

The magnetic phase diagram of the quarter-filled generalized Wigner lattice with nearest- and next-nearest-neighbor hopping t_1 and t_2 is explored. We find a region at negative t_2 with fully saturated ferromagnetic ground states that we attribute to kinetic exchange. Such interaction disfavors antiferromagnetism at t_2 <0 and stems from virtual excitations across the charge gap of the Wigner lattice, which is much smaller than the Mott-Hubbard gap proportional to U. Remarkably, we find a strong dependence of the charge structure factor on magnetism even in the limit U to infinity, in contrast to the expectation that charge ordering in the Wigner lattice regime should be well described by spinless fermions. Our results, obtained using the density-matrix renormalization group and exact diagonalization, can be transparently explained by means of an effective low-energy Hamiltonian.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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