Zr掺杂对石墨烯纳米带电学性质的影响研究
发布时间：2019-01-17 09:09
【摘要】：石墨烯纳米带(GNRs)因其具有的特殊几何结构和优越的电学性质,在纳米电子学领域具有潜在应用价值,而过渡金属元素在GNRs上的吸附或掺杂而使GNRs具有更多优异的电学磁学特性,因而受到了越来越多的关注。本文采用基于密度泛函理论的第一性原理,首先对未掺杂的不同自旋极化构型下GNRs的电学磁学特性进行计算,接着对Zr吸附、掺杂的GNRs的稳定性、电学磁学性质、传输特性进行了理论计算。主要研究内容如下:(1)研究了四种不同自旋极化构型的锯齿形石墨烯纳米带(ZGNRs)的电子结构和传输特性。计算结果显示,ZGNRs的电子传输特性很大程度上受到纳米带边缘的电子自旋结构的影响。对于平行的自旋组态(spin-parallel)结构来说,在低偏压下其电流-电压是线性关系;对于反平行的自旋组态(spin-antiparallel)结构,其传输特性具有很强的自旋极化依赖性,这样的性质使得该结构可以作为潜在的自旋滤波器;而对于另外两个自旋组态结构,可以明显看出其具有半导体特性,在低偏压时,该结构具有很强的磁致电阻(magneto-resistance,MR)。(2)研究了在扶手椅型石墨烯纳米带(AGNR)中吸附Zr元素的稳定性、电子结构以及传输特性。研究结果表明,Zr原子吸附在纳米带边缘更加稳定;AGNR吸附Zr原子后体系均具有铁磁性(ferromagnetic,FM),具有明显的金属性和自旋过滤现象,各体系还出现了明显的负微分电阻效应。(3)研究了Zr元素在AGNR上不同位置、不同浓度的掺杂的5种Zr-AGNR构型,计算了各构型的结构稳定性、电子结构及传输特性。研究结果表明,各构型均表现为非磁性(non-magnetic);在D型掺杂中,Zr原子掺杂在AGNR边缘使体系更稳定,而T型掺杂体系稳定性最强;AGNR掺杂Zr元素后体系均具有金属性:D型掺杂金属性比T型掺杂强;双边同时掺杂的金属性比单边掺杂强。各体系的电子正向导通的通道主要是Zr原子链。(4)研究了Zr在锯齿形石墨烯纳米带中不同位置、不同浓度掺杂的5种Zr-ZGNR的稳定性、电子结构及传输特性。计算结果表明不同结构表现出不同的磁性。Zr原子掺杂在ZGNR边缘使得体系更加稳定,各掺杂体系均具有金属性,且双边掺杂金属性比单边掺杂强。Z-E2、Z-E1和Z-P1在偏压较高时出现了微小的负微分电阻现象。各体系的电子正向导通的通道主要为Zr原子链。
[Abstract]:Graphene nanobelts (GNRs) have potential applications in the field of nanoelectronics due to their special geometric structure and superior electrical properties. Due to the adsorption or doping of transition metal elements on GNRs, GNRs has more and more excellent electrical magnetic properties, so it has attracted more and more attention. In this paper, the first principle based on density functional theory is used to calculate the electrical magnetic properties of GNRs under different spin polarization configurations without doping, and then the adsorption of Zr, the stability of doped GNRs, and the electrical magnetic properties of GNRs are studied. The transmission characteristics are calculated theoretically. The main contents are as follows: (1) the electronic structure and transport properties of four zigzag graphene nanoribbons (ZGNRs) with different spin-polarized configurations have been investigated. The results show that the electron transport characteristics of ZGNRs are greatly affected by the electron spin structure at the edge of the nanobelts. For parallel spin configuration (spin-parallel) structures, the current-voltage relationship is linear at low bias voltage. For the anti-parallel spin configuration (spin-antiparallel) structure, its transmission characteristics are highly spin polarization-dependent, which makes the structure can be used as a potential spin filter. For the other two spin-configuration structures, it can be seen that they have semiconductor properties. At low bias voltage, the structure has a strong magnetoresistance (magneto-resistance,). MR). (2) the stability, electronic structure and transport properties of Zr elements adsorbed on the armchair graphene nanobelts (AGNR) were investigated. The results show that the adsorption of Zr atoms on the edge of nanobelts is more stable. After AGNR adsorbs Zr atoms, all the systems have ferromagnetism (ferromagnetic,FM), obvious gold properties and spin filtration phenomena. There is also a negative differential resistance effect in each system. (3) the different positions of Zr elements on AGNR have been studied. The structure stability, electronic structure and transport characteristics of five kinds of Zr-AGNR with different concentrations were calculated. The results show that all the configurations are nonmagnetic (non-magnetic), in D-type doping, Zr atom doping at the edge of AGNR makes the system more stable, while T-type doping system has the strongest stability. The gold properties of AGNR doped with Zr elements are stronger than that of T-type doping, and that of bilateral doping is stronger than that of one-sided doping. The electron forward conduction channel of each system is mainly Zr atomic chain. (4) the stability, electronic structure and transport properties of five kinds of Zr-ZGNR doped with different positions and different concentrations of Zr in zigzag graphene nanobelts have been studied. The calculated results show that different structures exhibit different magnetic properties. Doping of Zr atoms on the edge of ZGNR makes the system more stable. All doping systems have gold properties, and the properties of bilateral doping are stronger than that of unilateral doping. Z-E1 and Z-P1 show small negative differential resistance at high bias voltage. The electron forward conduction channel of each system is mainly Zr atomic chain.
【学位授予单位】：广西大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：O469;TB383.1
本文编号：2409859
[Abstract]:Graphene nanobelts (GNRs) have potential applications in the field of nanoelectronics due to their special geometric structure and superior electrical properties. Due to the adsorption or doping of transition metal elements on GNRs, GNRs has more and more excellent electrical magnetic properties, so it has attracted more and more attention. In this paper, the first principle based on density functional theory is used to calculate the electrical magnetic properties of GNRs under different spin polarization configurations without doping, and then the adsorption of Zr, the stability of doped GNRs, and the electrical magnetic properties of GNRs are studied. The transmission characteristics are calculated theoretically. The main contents are as follows: (1) the electronic structure and transport properties of four zigzag graphene nanoribbons (ZGNRs) with different spin-polarized configurations have been investigated. The results show that the electron transport characteristics of ZGNRs are greatly affected by the electron spin structure at the edge of the nanobelts. For parallel spin configuration (spin-parallel) structures, the current-voltage relationship is linear at low bias voltage. For the anti-parallel spin configuration (spin-antiparallel) structure, its transmission characteristics are highly spin polarization-dependent, which makes the structure can be used as a potential spin filter. For the other two spin-configuration structures, it can be seen that they have semiconductor properties. At low bias voltage, the structure has a strong magnetoresistance (magneto-resistance,). MR). (2) the stability, electronic structure and transport properties of Zr elements adsorbed on the armchair graphene nanobelts (AGNR) were investigated. The results show that the adsorption of Zr atoms on the edge of nanobelts is more stable. After AGNR adsorbs Zr atoms, all the systems have ferromagnetism (ferromagnetic,FM), obvious gold properties and spin filtration phenomena. There is also a negative differential resistance effect in each system. (3) the different positions of Zr elements on AGNR have been studied. The structure stability, electronic structure and transport characteristics of five kinds of Zr-AGNR with different concentrations were calculated. The results show that all the configurations are nonmagnetic (non-magnetic), in D-type doping, Zr atom doping at the edge of AGNR makes the system more stable, while T-type doping system has the strongest stability. The gold properties of AGNR doped with Zr elements are stronger than that of T-type doping, and that of bilateral doping is stronger than that of one-sided doping. The electron forward conduction channel of each system is mainly Zr atomic chain. (4) the stability, electronic structure and transport properties of five kinds of Zr-ZGNR doped with different positions and different concentrations of Zr in zigzag graphene nanobelts have been studied. The calculated results show that different structures exhibit different magnetic properties. Doping of Zr atoms on the edge of ZGNR makes the system more stable. All doping systems have gold properties, and the properties of bilateral doping are stronger than that of unilateral doping. Z-E1 and Z-P1 show small negative differential resistance at high bias voltage. The electron forward conduction channel of each system is mainly Zr atomic chain.
【学位授予单位】：广西大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：O469;TB383.1
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