發(fā)布時(shí)間：2018-01-19 23:24

  本文關(guān)鍵詞： 石墨烯納米帶 邊界勢(shì) 單邊量子谷霍爾相 量子自旋霍爾相　出處：《新疆大學(xué)》2017年碩士論文　論文類型：學(xué)位論文

【摘要】：石墨烯具有獨(dú)特的蜂窩狀晶格結(jié)構(gòu)和特殊的電子輸運(yùn)性質(zhì),在零能附近的電子具有線性色散關(guān)系和零帶隙的能帶結(jié)構(gòu)。本文中我們首先簡(jiǎn)單地介紹了石墨烯的結(jié)構(gòu)、物理特性和制備方法以及應(yīng)用前景。接著介紹了采用的理論模型和研究方法。最后我們采用緊束縛模型和格林函數(shù)方法,系統(tǒng)地研究鋸齒型石墨烯納米帶在外場(chǎng)作用下的能帶結(jié)構(gòu)和輸運(yùn)性質(zhì)。首先,我們研究了在垂直面內(nèi)電場(chǎng)和磁場(chǎng)共同作用下鋸齒型石墨烯納米帶的拓?fù)潆娮討B(tài)。我們發(fā)現(xiàn)邊界態(tài)和體態(tài)在零能附近都是局域態(tài),且此系統(tǒng)具有自旋極化的電子態(tài)和量子化的輸運(yùn)性質(zhì)。同時(shí),系統(tǒng)中存在一個(gè)以螺旋邊界態(tài)和傾斜體態(tài)為特征的量子自旋霍爾相。通過(guò)調(diào)節(jié)費(fèi)米能和面內(nèi)電場(chǎng),可以實(shí)現(xiàn)拓?fù)湎嘧儭ｋ娮討B(tài)對(duì)自旋和電荷的輸運(yùn)性質(zhì)起到了重要的作用,我們?cè)谒亩私Y(jié)構(gòu)中計(jì)算了相應(yīng)的自旋和電荷的霍爾電導(dǎo)。其次,我們研究了在邊界勢(shì)調(diào)控下鋸齒狀邊緣石墨烯納米帶的電子性質(zhì)。當(dāng)空間反演對(duì)稱性被子晶格勢(shì)和邊界勢(shì)破壞時(shí),系統(tǒng)中存在量子谷霍爾相和單邊的量子谷霍爾相。當(dāng)考慮自旋-軌道相互作用時(shí),邊界態(tài)對(duì)于谷指標(biāo)和自旋指標(biāo)都具有螺旋性,系統(tǒng)中可以同時(shí)存在量子谷霍爾相和量子自旋霍爾相。我們期待這些結(jié)果能夠在自旋電子和谷電子器件上得到應(yīng)用。
[Abstract]:Graphene has unique honeycomb lattice structure and special electron transport properties. The electron near zero energy has a linear dispersion relation and a band structure with zero band gap. In this paper, the structure of graphene is introduced briefly. Physical properties, preparation methods and application prospects. Then the theoretical model and research methods are introduced. Finally, we use the tight-binding model and Green's function method. The energy band structure and transport properties of zigzag graphene nanoribbons under external field were systematically studied. We study the topological electronic states of zigzag graphene nanoribbons under the interaction of electric field and magnetic field in the vertical plane. We find that both the boundary state and the bulk state are local states near zero energy. The system has the properties of spin polarized electronic state and quantized transport. At the same time, there is a quantum spin Hall phase characterized by spiral boundary state and tilted state. The Fermi energy and the in-plane electric field are adjusted. Electronic states play an important role in the transport properties of spin and charge. We calculate the Hall conductance of spin and charge in the four-terminal structure. We study the electronic properties of zigzag edge graphene nanobelts under the control of boundary potential. When the space inversion symmetry quilt lattice potential and boundary potential are destroyed. Quantum valley Hall phase and one-sided quantum valley Hall phase exist in the system. When the spin-orbit interaction is considered, the boundary state is spiral for both the valley and spin indices. Both quantum valley Hall phase and quantum spin Hall phase can exist in the system, and we hope that these results can be applied to both spin electrons and valley electronic devices.
【學(xué)位授予單位】：新疆大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2017
【分類號(hào)】：O613.71;TB383.1
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本文編號(hào)：1445917