Ground state phase diagram of the half-filled bilayer Hubbard model
Ground state phase diagram of the half-filled bilayer Hubbard model
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半填充双层哈伯德模型的基态相图
DOI：
10.1103/physrevb.90.195131
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发表时间：
2014
影响因子：
3.7
通讯作者：
S. Wessel
中科院分区：
文献类型：
--
作者：
M. Golor;T. Reckling;L. Classen;M. M. Scherer;S. Wessel
采用相结合的功能重整化群计算和投影行列式量子Monte Carlo模拟，我们研究了在半填充的正方形晶格双层的哈伯德模型。从这个组合的分析，我们得到一个全面的帐户的基态相图相对于系统的金属和（反铁磁有序）莫特绝缘以及带绝缘区域的程度。通过一个无偏的功能重整化群的方法，我们表现出的反铁磁莫特绝缘状态的自由金属态的相关不稳定性，诱导任何弱有限的现场排斥。仔细分析的量子蒙特卡罗数据后，我们解决了识别这种反铁磁基态有限层间跳跃在弱耦合制度，非单调有限尺寸的修正所示的困难，涉及到的两层费米表面结构的金属相。另一方面，量子蒙特卡罗模拟非常适合于识别莫特绝缘相和带绝缘体之间的过渡中强耦合制度。在这里，我们比较我们的数值计算结果，从功能重整化群过程中获得的过渡区的迹象。
Employing a combination of functional renormalization group calculations and projective determinantal quantum Monte Carlo simulations, we examine the Hubbard model on the square lattice bilayer at half filling. From this combined analysis, we obtain a comprehensive account of the ground-state phase diagram with respect to the extent of the system's metallic and (antiferromagnetically ordered) Mott-insulating as well as band-insulating regions. By means of an unbiased functional renormalization group approach, we exhibit the antiferromagnetic Mott-insulating state as the relevant instability of the free metallic state, induced by any weak finite on-site repulsion. Upon performing a careful analysis of the quantum Monte Carlo data, we resolve the difficulty of identifying this antiferromagnetic ground state for finite interlayer hopping in the weak-coupling regime, where nonmonotonic finite-size corrections are shown to relate to the two-sheeted Fermi surface structure of the metallic phase. On the other hand, quantum Monte Carlo simulations are well suited to identify the transition between the Mott-insulating phase and the band insulator in the intermediate-to-strong coupling regime. Here, we compare our numerical findings to indications for the transition region obtained from the functional renormalization group procedure.