Majorana边态导致的交叉Andeev反射研究-凝聚态物理专业毕业论文.docx

Abstract In recent years，the Majorana fermion attract more and more researchers for its unique property and the broad prospects in the field of quantum computers in condensed matter physics．In the continuous exploration，we have obtained a series of great breakthrough．Of all these researches，due to the peculiar physical nature and potential application，the heterogeneous coupled Majorana fermions to superconductor has been widely studied．It was found that the edge state of Majorana fermions could induce Andreev reflection but not better crossed Andreev reflection In this article we start with the research on crossed Andreev reflection induced by the Majorana edge state．Fist，we confirm that our central area is Majorana edge state，then we calculate the electron transport of the junction which coupling normal semiconductor to superconductor，in order to enhance the effect of crossed Andreev reflection，we propose a heterogeneous which coupled ferromagnetic to superconductor，finally we considered different strength of disorder to our results．It was found that the crossed Andreev reflection was enhanced due to the ferromagnetic contrast to the normal semiconductor；we can achieve a structure similar to platform with the proper setting of parameters of both external and internal，which dominant in the current；considering the disorder strength，the structure Can keep steady under disorder with small strength，until under strong strength，the platform destroyed and eventually degenerate into a smaller and stable numerical value．． Key words：Majorana fermion，ferromagnetic，edge state，crossed Andreev reflection IV 万方数据  目 录 摘要 ．． ．．．．．． ．．．． ．．．．．．．．． ．． ．．．．III Abstract ．．．．．．．．．．．．．． ．．．．．．．．．．． ．． ． ．． ．．．．．IV 目录 ．． ．．．．．．．．．．．．．． ．．．．．．．． ． ．． ．．．．．V 1绪论．． ．．．．．．．．．．．．．． ．．．．．．．．．．．．． ．．．．．．．．． ．．．．．． l 1．1 Majorana费米子的提出及其特性．．．．．．．． ．．．．．．．．．． ．．．．．． ．．1 1．2 Majorana费米子的探寻历程． ．．2 1．3 Andreev反射和交叉Andreev反射．．．．．．．．． ．．．．．