FERROMAGNETISM IN HUBBARD MODELS - LOW-DENSITY ROUTE

被引：66

作者：

MULLERHARTMANN, E

机构：

[1] Institut für Theoretische Physik, Universität zu Köln, Köln, 50937

来源：

JOURNAL OF LOW TEMPERATURE PHYSICS | 1995年 / 99卷 / 3-4期

关键词：

D O I：

10.1007/BF00752307

中图分类号：

O59 [应用物理学];

学科分类号：

摘要：

Thirty years ago the Hubbard model was introduced by Gutzwiller, Hubbard and Kanamori with the main purpose of mimicking the ferromagnetism of transition metals. Soon after, Nagaoka and Thouless pointed out a basic mechanism for ferromagnetism in strongly correlated electron systems by studying the motion of a single hole in a half-filled Hubbard model. This important work was hoped to shed light onto metallic ferromagnetism from Me low doping regime Unfortunately, this low doping route towards ferromagnetism has not been succcessful as far as rigorous results for finite doping concentrations are concerned. In the work presented here, we start from the opposite limit of low particle concentrations, In, this limit we provide the first proof of a fully polarized metallic ground state for a Hubbard model. The proof proceeds by mapping Hubbard ''zigzag'' chains onto a continuum model with an additional degree of freedom and local First Hund's rule coupling. For this model the maximum total spin multiplet is shown to be the unique ground state for infinite Hubbard coupling. Our proof may open a low density route towards the understanding of the ferromagnetism of Hubbard models.

引用

页码：349 / 354

页数：6

共 22 条

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