非共價表面修飾對鋸齒型碳化硅納米條帶能帶結構的有效調(diào)控
發(fā)布時間：2019-03-28 07:35
【摘要】：近十年來，石墨烯、碳納米條帶等在實驗上的成功合成預示著材料科學進入了新時代，，激起了人們在原子水平上研究低維碳納米體系和無機納米體系的結構和物理化學特性的極大熱情。碳化硅納米條帶作為碳納米條帶的結構類似物，以其優(yōu)越的特性（熱穩(wěn)定性、化學穩(wěn)定性高等）已引起了實驗和理論工作者的高度關注。然而，由于鋸齒型碳化硅納米條帶（zSiCNR）存在鐵磁態(tài)和反鐵磁態(tài)能量簡并的問題，嚴重制約了其在多功能納米器件、納米自旋器件等多領域中的實際應用。 在本論文工作中，基于第一性原理計算，我們提出利用非共價π-π相互作用在zSiCNR表面吸附具有吸/給電子能力的有機分子（如TCNQ/TTF）去突破該瓶頸，達到有效調(diào)控體系電學和磁學行為的目的。研究表明這些有機分子能穩(wěn)定地吸附在zSiCNR表面（吸附能為-71.3~-184.0kJmol-1），并與zSiCNR之間發(fā)生了明顯的電荷轉(zhuǎn)移過程，使條帶內(nèi)部的靜電勢發(fā)生了顯著的變化（如同施加一個外加電場），從而打破了zSiCNR體系磁性簡并的瓶頸問題，并有效地調(diào)節(jié)其能帶結構：當TTF和TCNQ分子位于條帶中心的時候相應體系都表現(xiàn)出鐵磁金屬特性；隨著吸附分子從中心移到邊緣，吸附TTF的體系仍保持鐵磁金屬特性，而相應的TCNQ體系則表現(xiàn)出了反鐵磁半金屬性。這些有趣的結果將有利于推進硅碳基納米材料在電子自旋器件和多功能納米器件領域中的實際應用。
[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.
【學位授予單位】：吉林大學
【學位級別】：碩士
【學位授予年份】：2015
【分類號】：TB383.1
本文編號：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.
【學位授予單位】：吉林大學
【學位級別】：碩士
【學位授予年份】：2015
【分類號】：TB383.1
【參考文獻】
相關期刊論文 前1條
1 王世忠,徐良瑛,束碧云,肖兵,莊擊勇,施爾畏;SiC單晶的性質(zhì)、生長及應用[J];無機材料學報;1999年04期
本文編號：2448666
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