arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 1904.03067cond-mat.str-elcond-mat.supr-con
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三角格子准一维电荷转移固体理论

Theory of triangular lattice quasi-one-dimensional charge-transfer solids

R. T. Clay, N. Gomes, S. Mazumdar

摘要:

最近对准一维三角晶格有机电荷转移固体磁性的研究和超导电性的发现表明,有效1/2填充带哈伯德模型对这些和相关系统的严重局限性。我们的计算研究,这些材料在1/4填充带哈伯德模型,其中的有机单体分子,而不是他们的二聚体,构成的网站的哈密顿量是能够再现的实验结果。我们将kappa-(BEDT-TTF)_2B(CN)_4的自旋能隙转变归因于二维双电子晶体的形成,并作出了可检验的预言:自旋能隙将伴随着电荷有序化和两个方向的倍周期。我们发现,对于kappa-(BEDT-TTF)_2CF_3SO_3的能带参数,Hubbard排斥作用增强了超导配对关联的长程分量。这些结果有力地支持了我们最近提出的超导电性的价键理论。

英文摘要:

Recent investigations of the magnetic properties and the discovery of superconductivity in quasi-one-dimensional triangular lattice organic charge-transfer solids have indicated the severe limitations of the effective 1/2-filled band Hubbard model for these and related systems. Our computational studies of these materials within a 1/4-filled band Hubbard model in which the organic monomer molecules, and not their dimers, constitute the sites of the Hamiltonian are able to reproduce the experimental results. We ascribe the spin gap transition in kappa-(BEDT-TTF)_2B(CN)_4 to the formation of a two-dimensional paired-electron crystal and make the testable prediction that the spin gap will be accompanied by charge-ordering and period doubling in two directions. We find enhancement of the long-range component of superconducting pairing correlations by the Hubbard repulsive interaction for band parameters corresponding to kappa-(BEDT-TTF)_2CF_3SO_3. The overall results strongly support a valence bond theory of superconductivity we have proposed recently.

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