拓扑绝缘体表面电子在非均匀磁场下的束缚态与能谱  

Energy Spectrum and Bound States of Electron on the Surface of Topological Insulator

作　　者：王俊亚[1] 聂一行[1] 

机构地区：[1]山西大学理论物理研究所,山西太原030006

出　　处：《山西大学学报（自然科学版）》2013年第2期214-218,共5页Journal of Shanxi University(Natural Science Edition)

基　　金：国家自然科学基金(11274208)

摘　　要：计算了拓扑绝缘体表面上狄拉克电子在磁势约束下的能谱,分别就圆形和环形约束量子点给出了通过磁势垒约束狄拉克电子形成束缚态的条件.量子点半径趋于零时,狄拉克电子占据朗道能级,半径增大时出现(n,m)态和(n,-m)态的简并.环形量子点中内外半径之比小于某个临界值时,才会出现束缚态,反之,退化到朗道能级.这些束缚能级可以通过改变约束半径或磁场大小来调制,对设计拓扑保护的量子器件有重要应用.The energy spectrum and bound states of Dirac electron on the surface of topological insulator un- der the restriction of magnetic potential are investigated. We discuss the influence of the radius of quantum dot on the energy spectrum and give the condition of the form of bound states in a circular quantum dot by the restriction of magnetic potential harrier. When the radius of the circular quantum dot approach zero Db rac electron occupies Landau level and the state （n,rn） and （n,--m） degenerate for the large radius. For the ring quantum dot, the bound states emerge only when the ratio of the inner and outer radii of the ring is less than a critical value. When the ratio is larger than the critical value, the energy level restore Landau level. The bound levels may be modulated by changing the magnetic field and the radius of the dot or ring, which is useful in designing topologically-protected quantum devices.

关 键 词：拓扑绝缘体 狄拉克电子 束缚态 

分 类 号：O413[理学—理论物理]