arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 1111.3751cond-mat.str-el
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局域近似下多电子模型的能谱演化和金属-绝缘体相变

Evolution of the spectrum and the metal-insulator transition in local approximations for many-electron models

A. O. Anokhin, A. V. Zarubin, V. Yu. Irkhin

摘要:

在多电子s-d交换模型和哈伯德模型的框架下,导出了多电子哈伯德X算符表象中单粒子延迟格林函数的自洽方程.我们分析了单点近似的一般结构及其与相干势近似和动态有效场论的联系。利用自洽近似,我们详细研究了电子光谱的演化与模型参数(耦合常数,载流子浓度)的图片。研究了各种因素(Kondo多电子散射、阻尼效应、局域矩子系统动力学)对相互作用系统态密度N(E)形状的影响。它示出的定位器表示的使用允许避免在某些情况下的非解析近似表达式的格林函数。我们的方法使人们能够再现,在某些值的参数,三峰结构的N(E)附近的金属-绝缘体的转变。

英文摘要:

In the framework of the many-electron s-d exchange model and Hubbard model, self-consistent equations are derived for the one-particle retarded Green's function in the many-electron Hubbard X-operator representation. We analyze the general structure of the single-site approximations and their connection with the coherent potential approximation (CPA) and dynamic effective field theory (DMFT). Using the self-consistent approximation, we examine in detail the picture of the evolution of the electron spectrum with the model parameters (coupling constants, the concentration of charge carriers). The influence of various factors (Kondo many-electron scattering, smearing due to damping, dynamics of localized moment subsystem) on the shape of the density of states N(E) in the interacting system is investigated. It is shown that the use of the locator representation allows to avoid in some cases the non-analyticity in approximate expressions for the Green's functions. Our approach enables one to reproduce, at certain values of the parameters, three-peak structure of N(E) near the metal-insulator transition.

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