金属-石墨烯混合系统中过渡族金属原子局域磁矩研究

	金属-石墨烯混合系统中过渡族金属原子局域磁矩研究
Alternative Title	Transition Metal Atoms Localized Magnetic Moments in Metal-Graphene Hybrided System
	张欄
Thesis Advisor	罗洪刚
	2014-05-22
Degree Grantor	兰州大学
Place of Conferral	兰州
Degree Name	学士
Keyword	Anderson模型磁性杂质石墨烯
Abstract	Anderson模型是处理磁性杂质问题的重要模型，在Hartree-Fock近似下该模型可以用于研究磁性杂质在金属（半导体、石墨烯等）体系能否表现出局域磁矩的问题。本文总结了吸附磁性杂质的金属及石墨烯体系局域磁矩态存在性方面的研究工作。研究结果表明两者局域磁矩态与顺磁态边界线形状有很大不同，调节Hamiltonian参数时金属中两种状态的边界线呈现对称结构，后者表现出强烈的非对称性。进一步我们考察了金属探针测量时吸附磁性杂质的石墨烯体系的局域磁矩，为此我们构造了金属-石墨烯混合体系的Anderson模型，并数值计算了相应的局域磁化态存在的参数范围。我们得到混合体系的临界曲线主要决定于金属探针与磁性杂质的耦合强度。随着金属探针与磁性杂质耦合强度的增强，磁性杂质磁性与顺磁边界线形状逐渐由石墨烯情形过渡为金属情形或者由金属情形过渡为石墨烯情形。在石墨烯和金属与磁性杂质耦合大小相当时数值上会出现一些不稳定情况。
Other Abstract	Anderson model is an important model to deal with magnetic impurity, and under the Hartree-Fock Approximation ,this model can be used to study the localized magnetic moments on metal (semi-conductor, graphene and so on). In this thesis we review the work on the Anderson impurity model, which the transition metal atom is doped into the metal and adsorbed on the surface of graphene. The research indicated that the boundary between magnetic and non-magnetic regions of two systems is so different. In the metal case it is symmetric, while in the graphene case it is strongly asymmetric. In order to study the localized magnetic moments in grapheme with a magnetic impurity atom and a metal probe, then we use the metal-graphene hybrided system’s Anderson model, and numerically calculate some variables and the region that exit localized magnetic moments. We find that the boundary between magnetic and non-magnetic region mainly depends on the metal probe and magnetic coupling strength of impurity. With the increasing of the coupling strength of impurity, magnetic impurity boundary between magnetic and non-magnetic gradually transfers from graphene situation to the metal case, or transfer from the metal situation to the graphene case. It is also found that the states are unstable as the coupling strengths between the metal and the impurity and between the graphene and the impurity are in the same order, which need further theoretical study.
URL	查看原文
Language	中文
Document Type	学位论文
Identifier	https://ir.lzu.edu.cn/handle/262010/229695
Collection	物理科学与技术学院
Recommended Citation GB/T 7714	张欄. 金属-石墨烯混合系统中过渡族金属原子局域磁矩研究[D]. 兰州. 兰州大学,2014.

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