The study of two-particle response functions in strongly correlated electron systems within the dynamical mean field theory
The study of two-particle response functions in strongly correlated electron systems within the dynamical mean field theory
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动态平均场理论中强相关电子系统中双粒子响应函数的研究
DOI：
10.7282/t3639n99
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发表时间：
2011
影响因子：
8.6
通讯作者：
Hyowon Park
中科院分区：
文献类型：
--
作者：
Hyowon Park
在动态平均场理论中强关联电子系统中的两粒子响应函数的研究Hyowon Park博士论文主任：在这篇论文中，我们解决了强关联电子系统中的各种问题，这可以通过非微扰动力学平均场理论（DMFT）来解决。方法使用连续时间量子蒙特卡罗方法作为杂质求解器。首先，我们在U = ∞ Hubbard模型中重新讨论了旧的Nagaoka铁磁性问题，并研究了铁磁态的稳定性作为温度，掺杂水平和次近邻跳跃t的函数。然后，我们解决的Mott过渡的性质，在二维哈伯德模型在半填充使用集群DMFT。聚类DMFT可以通过将相关性处理的空间范围扩展到有限的聚类大小来包含DMFT之外的短程相关性。非局域关联大大降低了临界相互作用U，并改变了相图中过渡线的形状。然后，我们从从头计算的角度，通过使用密度泛函理论（DFT）和DMFT相结合的方法计算单粒子激发谱，并提取两粒子不可约的
OF THE DISSERTATION The study of two-particle response functions in strongly correlated electron systems within the dynamical mean field theory by Hyowon Park Dissertation Director: Prof. Kristjan Haule In this thesis, we tackle various problems in strongly correlated electron systems, which can be addressed properly via the non-perturbative dynamical mean field theory (DMFT) approach using the continuous time quantum Monte Carlo method as an impurity solver. First, we revisit the old Nagaoka ferromagnetism problem in the U = ∞ Hubbard model and study the stability of the ferromagnetic state as a function of the temperature, the doping level, and the next-nearest-neighbor hopping t. We then address the nature of the Mott transition in the twodimensional Hubbard model at half-filling using cluster DMFT. Cluster DMFT can incorporate the short-range correlations beyond DMFT by extending the spatial range in which correlations are treated exactly to a finite cluster size. The non-local correlations reduce substantially the critical interaction U and modify the shape of the transition lines in the phase diagram. We then concentrate on the calculation of two-particle response functions from the ab initio perspective by means of computing the one-particle excitation spectrum using the combination of the density functional theory (DFT) and DMFT and extracting the two-particle irreducible
影响因子：
44.1
作者：
Gull, Emanuel;Millis, Andrew J.;Werner, Philipp
通讯作者：
Werner, Philipp