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arXiv 2403.09862cond-mat.str-el
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二维Hubbard模型中螺旋态到条纹态的转变

Spiral to stripe transition in the two-dimensional Hubbard model

Robin Scholle, Walter Metzner, Demetrio Vilardi, Pietro M. Bonetti

AI总结:

本文在热力学极限下通过平均场方程和Landau自由能分析,完整刻画了二维Hubbard模型中螺旋态到条纹态的转变,发现随空穴掺杂增加依次出现Néel态、圆螺旋态、多螺旋态和条纹态,并给出包含涨落效应的定性相图。

摘要:

我们对具有较大次近邻跃迁和中等相互作用强度的正方晶格二维Hubbard模型的平均场相图获得了近乎完整的理解。特别地,我们阐明了螺旋相与条纹相之间过渡区域的性质。作为对先前在大型有限晶格上的实空间Hartree-Fock计算[Phys. Rev. B 108, 035139 (2023)]的补充,我们直接在热力学极限下求解共面单向磁序的平均场方程,并通过Landau自由能分析确定了刚好低于平均场临界温度$T^*$时磁态的性质。对于填充因子$n \geq 1$,磁序始终为Néel型;而对于$n \leq 1$,随着空穴掺杂的增加,发现如下磁态序列:Néel态、平面圆螺旋态、多螺旋态和共线自旋-电荷条纹态。多螺旋态是若干具有不同波矢的螺旋的叠加,并导致伴随的电荷序。最后,我们指出,继承自磁序的向列序和电荷序即使在存在涨落的情况下也能存活,并给出了相应的定性相图。

英文摘要:

We obtain an almost complete understanding of the mean-field phase diagram of the two-dimensional Hubbard model on a square lattice with a sizable next-nearest neighbor hopping and a moderate interaction strength. In particular, we clarify the nature of the transition region between the spiral and the stripe phase. Complementing previous [Phys. Rev. B 108, 035139 (2023)] real-space Hartree-Fock calculations on large finite lattices, we solve the mean-field equations for coplanar unidirectional magnetic order directly in the thermodynamic limit, and we determine the nature of the magnetic states right below the mean-field critical temperature $T^*$ by a Landau free energy analysis. While the magnetic order for filling factors $n \geq 1$ is always of Néel type, for $n \leq 1$ the following sequence of magnetic states is found as a function of increasing hole-doping: Néel, planar circular spiral, multi-spiral, and collinear spin-charge stripe states. Multi-spiral states are superpositions of several spirals with distinct wave vectors, and lead to concomitant charge order. We finally point out that nematic and charge orders inherited from the magnetic order can survive even in the presence of fluctuations, and we present a corresponding qualitative phase diagram.

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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