论文标题
局部矩与巡回反铁磁性：磁相图和各向异性方形晶格Hubbard模型的光谱特性
Local moments versus itinerant antiferromagnetism: magnetic phase diagram and spectral properties of the anisotropic square lattice Hubbard model
论文作者
论文摘要
使用动态平均场理论（CDMFT）的群集扩展，我们绘制了各向异性方形晶格哈伯德模型的磁相图，该模型最近邻邻纽伯爵内部$ t $和链链$ t _ {\ perp} $在半填充时跳跃。下一个最邻居跳跃的固定值$ t'= - t _ {\ perp}/2 $ $删除了费米表面的嵌套属性，并稳定了弱耦合方面的顺磁金属相。在各向同性和中度各向异性区域中，金属相在临界相互作用强度下，在远程抗铁磁（AF）的局部局部局部局部局部时刻，将旋转的熵在临界的相互作用强度下淬灭。它产生了与Mott-Heisenberg图片一致的一阶金属绝缘体过渡。相比之下，强烈的各向异性制度$ t _ {\ perp}/t \ Lessim 0.3 $显示与AF金属相和AF绝缘子之间的连续过渡有关的量子关键行为。因此，在CDMFT的当前框架内，充电间隙的开口是磁性驱动的，如Slater图片中所提倡的。我们还讨论了晶格 - 肛门型诱导的电子结构在相图的金属侧如何与量子关键的出现相关。
Using a cluster extension of the dynamical mean-field theory (CDMFT) we map out the magnetic phase diagram of the anisotropic square lattice Hubbard model with nearest-neighbor intrachain $t$ and interchain $t_{\perp}$ hopping amplitudes at half-filling. A fixed value of the next-nearest-neighbor hopping $t'=-t_{\perp}/2$ removes the nesting property of the Fermi surface and stabilizes a paramagnetic metal phase in the weak-coupling regime. In the isotropic and moderately anisotropic regions, a growing spin entropy in the metal phase is quenched out at a critical interaction strength by the onset of long-range antiferromagnetic (AF) order of preformed local moments. It gives rise to a first-order metal-insulator transition consistent with the Mott-Heisenberg picture. In contrast, a strongly anisotropic regime $t_{\perp}/t\lesssim 0.3$ displays a quantum critical behavior related to the continuous transition between an AF metal phase and the AF insulator. Hence, within the present framework of CDMFT, the opening of the charge gap is magnetically driven as advocated in the Slater picture. We also discuss how the lattice-anisotropy-induced evolution of the electronic structure on a metallic side of the phase diagram is tied to the emergence of quantum criticality.
