Dynamical Characteristics of the Mott transition: Examination of Doubloon Dynamics in a Triangular-lattice Hubbard Model
Dynamical Characteristics of the Mott transition: Examination of Doubloon Dynamics in a Triangular-lattice Hubbard Model
复制标题
莫特转变的动力学特征：三角晶格哈伯德模型中的达布隆动力学检验
DOI：
10.1016/j.phpro.2015.12.045
复制
发表时间：
2015
期刊：
影响因子：
--
通讯作者：
Toshihiro Sato and Hirokazu Tsunetsugu
中科院分区：
文献类型：
--
作者：
佐藤諒;横山寿敏;Toshihiro Sato and Hirokazu Tsunetsugu
基于团簇动力学平均场理论，研究了半满三角格子Hubbard模型中的动力学行为。数值计算使用基于强耦合展开的连续时间量子蒙特卡罗方法的求解器。我们研究了在Mott跃迁附近，随着库仑排斥的变化，时间域中的doublon和霍隆的最近邻动力学关联的变化。我们证明了最近邻的doublon-holon对表现出很强的吸引关联，特别是在绝缘相，而最近邻的doublon-doublon对表现出排斥关联。动力学相关函数在复平面上的轨迹提供了有用的信息。最近邻的doublon和霍隆在金属相的短时间动力学表明更大的波动比绝缘相。它们在复平面上的运动轨迹表明，doublon-holon对的短时动力学行为与doublon-doublon对的行为相反。我们发现，它们的动力学时间尺度可以用两个阶段中相位围绕长时间极限旋转π的周期来表征。在长时间区域中，波动在金属相中持续很长时间，而它们在绝缘相中很快消失。
Dynamics in a triangular-lattice Hubbard model is studied at half filling on the basis of the cluster dynamical mean field theory. Numerical calculations use a solver of the continuous-time quantum Monte Carlo method based on the strong-coupling expansion. We examine the change in the nearest-neighbor dynamical correlations of doublon and holon in the time domain with varying the Coulomb repulsion near the Mott transition. We demonstrate that the nearest-neighbor doublon-holon pair shows a strong attractive correlation, particularly in the insulating phase, while the nearest-neighbor doublon-doublon pair shows a repulsive correlation. Useful information is provided by the trajectories in the complex plane of the dynamical correlation functions. The short-time dynamics of the nearest-neighbor doublon and holon in the metallic phase indicates larger fluctuations than in the insulating phase. Their trajectories in the complex plane show that the short-time dynamics of the doublon-holon pair has an opposite behavior to that of the doublon-doublon pair. We find that their time scale of dynamics can be characterized by the period in which the phase rotatesπaround the long-time limit in both phases. In the long-time region, fluctuations persist up to a very long time in the metallic phase, while they quickly vanish in the insulating phase.