Two-dimensional disordered Mott metal-insulator transition
Two-dimensional disordered Mott metal-insulator transition
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DOI：
10.1103/physrevb.101.235112
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发表时间：
2020-06-02
影响因子：
3.7
通讯作者：
Miranda, E.
中科院分区：
文献类型：
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作者：
Suarez-Villagran, M. Y.;Mitsakos, N.;Miranda, E.
我们研究了无序情况下Mott金属-绝缘体转变的几个方面。我们的分析所基于的模型是无序Hubbard模型，这是能够捕获Mott金属-绝缘体转变的最简单的模型。我们通过统计动力学平均场理论（statDMFT）研究了这个模型。这个理论是动力学平均场理论（DMFT）的自然延伸，在过去的几年里，DMFT已经相对成功地用于描述干净情况下的莫特转变。与后一种理论的情况一样，statDMFT仅在其局部表现中包含电子相关效应。另一方面，无序的处理方式是结合安德森局部化效应。利用这种方法，我们分析了无序二维Mott跃迁，用量子Monte Carlo算法解决了相关的单杂质问题。我们发现了亚稳线，在这条线上金属和绝缘体不再是亚稳的。我们还研究了局部量的空间涨落，如自能和局部绿色函数，并显示了绝缘体内的金属区域的外观，反之亦然。我们对有限尺寸效应进行了分析，并表明，与Imry和Ma [Y. Imry和S. K. Ma，Phys. Rev. Lett. 35，1399（1975）.]，一级跃迁在热力学极限中模糊。我们分析了输运性质的映射到一个随机的经典电阻网络，并计算了平均电流及其分布在金属-绝缘体过渡。
We studied several aspects of the Mott metal-insulator transition in the disordered case. The model on which we based our analysis is the disordered Hubbard model, which is the simplest model capable of capturing the Mott metal-insulator transition. We investigated this model through statistical dynamical mean-field theory (statDMFT). This theory is a natural extension of dynamical mean-field theory (DMFT), which has been used with relative success in the past several years with the purpose of describing the Mott transition in the clean case. As is the case for the latter theory, statDMFT incorporates the electronic correlation effects only in their local manifestations. Disorder, on the other hand, is treated in such a way as to incorporate Anderson localization effects. With this technique, we analyzed the disordered two-dimensional Mott transition, using the quantum Monte Carlo algorithm to solve the associated single-impurity problems. We found spinodal lines at which the metal and insulator ceased to be metastable. We also studied spatial fluctuations of local quantities, such as self-energy and local Green's function, and showed the appearance of metallic regions within the insulator and vice versa. We carried out an analysis of finite-size effects and showed that, in agreement with the theorems of Imry and Ma [Y. Imry and S. K. Ma, Phys. Rev. Lett. 35, 1399 (1975).], the first-order transition is smeared in the thermodynamic limit. We analyzed transport properties by means of a mapping to a random classical resistor network and calculated both the average current and its distribution across the metal-insulator transition.