非共价表面修饰对锯齿型碳化硅纳米条带能带结构的有效调控
发布时间：2019-03-28 07:35
【摘要】：近十年来，石墨烯、碳纳米条带等在实验上的成功合成预示着材料科学进入了新时代，，激起了人们在原子水平上研究低维碳纳米体系和无机纳米体系的结构和物理化学特性的极大热情。碳化硅纳米条带作为碳纳米条带的结构类似物，以其优越的特性（热稳定性、化学稳定性高等）已引起了实验和理论工作者的高度关注。然而，由于锯齿型碳化硅纳米条带（zSiCNR）存在铁磁态和反铁磁态能量简并的问题，严重制约了其在多功能纳米器件、纳米自旋器件等多领域中的实际应用。 在本论文工作中，基于第一性原理计算，我们提出利用非共价π-π相互作用在zSiCNR表面吸附具有吸/给电子能力的有机分子（如TCNQ/TTF）去突破该瓶颈，达到有效调控体系电学和磁学行为的目的。研究表明这些有机分子能稳定地吸附在zSiCNR表面（吸附能为-71.3~-184.0kJmol-1），并与zSiCNR之间发生了明显的电荷转移过程，使条带内部的静电势发生了显著的变化（如同施加一个外加电场），从而打破了zSiCNR体系磁性简并的瓶颈问题，并有效地调节其能带结构：当TTF和TCNQ分子位于条带中心的时候相应体系都表现出铁磁金属特性；随着吸附分子从中心移到边缘，吸附TTF的体系仍保持铁磁金属特性，而相应的TCNQ体系则表现出了反铁磁半金属性。这些有趣的结果将有利于推进硅碳基纳米材料在电子自旋器件和多功能纳米器件领域中的实际应用。
[Abstract]:In the past decade, the successful synthesis of graphene, carbon nanobeles and so on in experiments indicates that material science has entered a new era. It has aroused great enthusiasm to study the structure and physical and chemical properties of low-dimensional carbon nano-system and inorganic nano-system at the atomic level. As a structural analogue of carbon nano-band, silicon carbide nanband has attracted much attention from both experimental and theoretical researchers for its superior properties (thermal stability and chemical stability). However, due to the energy degeneracy of ferromagnetic and antiferromagnetic states in the sawn-toothed silicon carbide nano-strip (zSiCNR), its application in multi-functional nano-devices, nano-spin devices and other fields has been seriously restricted. In this work, based on first-principles calculations, we propose to use the non-covalent 蟺-蟺 interaction to adsorb organic molecules (such as TCNQ/TTF) on the surface of zSiCNR, which have the ability to absorb / give electrons, to break through this bottleneck. To effectively regulate the electrical and magnetic behavior of the system. The results show that these organic molecules can be stably adsorbed on the surface of zSiCNR (the adsorption energy is-71.3~-184.0kJmol-1), and the charge transfer process between the molecules and zSiCNR is obvious. The electrostatic potential in the strip changed significantly (like applying an applied electric field), thus breaking the bottleneck of magnetic degeneracy in the zSiCNR system. The energy band structure of TTF and TCNQ molecules were adjusted effectively. The corresponding systems showed ferromagnetic and metallic properties when they were located at the center of the band. As the adsorbed molecules moved from the center to the edge, the adsorption system of TTF remained ferromagnetic metal, while the corresponding TCNQ system showed antiferromagnetic semi-gold property. These interesting results will facilitate the practical application of silicon-carbon-based nanomaterials in the field of electronic spin devices and multi-functional nano-devices.
【学位授予单位】：吉林大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TB383.1
本文编号：2448666
[Abstract]:In the past decade, the successful synthesis of graphene, carbon nanobeles and so on in experiments indicates that material science has entered a new era. It has aroused great enthusiasm to study the structure and physical and chemical properties of low-dimensional carbon nano-system and inorganic nano-system at the atomic level. As a structural analogue of carbon nano-band, silicon carbide nanband has attracted much attention from both experimental and theoretical researchers for its superior properties (thermal stability and chemical stability). However, due to the energy degeneracy of ferromagnetic and antiferromagnetic states in the sawn-toothed silicon carbide nano-strip (zSiCNR), its application in multi-functional nano-devices, nano-spin devices and other fields has been seriously restricted. In this work, based on first-principles calculations, we propose to use the non-covalent 蟺-蟺 interaction to adsorb organic molecules (such as TCNQ/TTF) on the surface of zSiCNR, which have the ability to absorb / give electrons, to break through this bottleneck. To effectively regulate the electrical and magnetic behavior of the system. The results show that these organic molecules can be stably adsorbed on the surface of zSiCNR (the adsorption energy is-71.3~-184.0kJmol-1), and the charge transfer process between the molecules and zSiCNR is obvious. The electrostatic potential in the strip changed significantly (like applying an applied electric field), thus breaking the bottleneck of magnetic degeneracy in the zSiCNR system. The energy band structure of TTF and TCNQ molecules were adjusted effectively. The corresponding systems showed ferromagnetic and metallic properties when they were located at the center of the band. As the adsorbed molecules moved from the center to the edge, the adsorption system of TTF remained ferromagnetic metal, while the corresponding TCNQ system showed antiferromagnetic semi-gold property. These interesting results will facilitate the practical application of silicon-carbon-based nanomaterials in the field of electronic spin devices and multi-functional nano-devices.
【学位授予单位】：吉林大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TB383.1
【参考文献】
相关期刊论文 前1条
1 王世忠,徐良瑛,束碧云,肖兵,庄击勇,施尔畏;SiC单晶的性质、生长及应用[J];无机材料学报;1999年04期
本文编号：2448666
本文链接：https://www.wllwen.com/kejilunwen/cailiaohuaxuelunwen/2448666.html
