Andreev reflection in a proximity junction of graphene: Influence of a naturally formed pn junction
Andreev reflection in a proximity junction of graphene: Influence of a naturally formed pn junction
复制标题
石墨烯邻近结中的安德烈夫反射：自然形成的 pn 结的影响
DOI：
10.1088/1742-6596/969/1/012155
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发表时间：
2018
期刊：
影响因子：
--
通讯作者：
A. Kanda
中科院分区：
文献类型：
--
作者：
Y. Takane;A. Kanda
我们从理论上研究了用块状超导体部分覆盖石墨烯片制成的邻近结中的电子输运。这样的系统作为一个正常的导体-超导体（NS）结，其电子输运性质主要是由安德烈耶夫反射（AR）。在这种NS结中，石墨烯的电荷中性点（CNP）必须在空间上变化，作为从超导体诱导的过量载流子的渗透的结果。考虑到这一点，在电子掺杂的情况下，我们计算的微分电导G NS的石墨烯NS结。由于未覆盖区域中CNP的变化，在费米能穿过CNP的点处自然形成平滑的pn结。由此产生的pn结导致不寻常的行为的G NS。例如，在GNS中出现的共振峰结构反映了由pn结产生准束缚态的事实。
We theoretically study the electron transport in a proximity junction made by partially covering a graphene sheet with a bulk superconductor. Such a system serves as a normal conductor–superconductor (NS) junction and its electron transport properties are mainly governed by Andreev reflection (AR). In this NS junction, the charge neutrality point (CNP) of graphene must spatially vary as a result of the penetration of excess carriers induced from the superconductor. By taking this into account in the electron-doped case, we calculate the differential conductance G NS of the graphene NS junction. Owing to the variation of the CNP in the uncovered region, a smooth pn junction is naturally formed at the point where the Fermi energy crosses the CNP. The resulting pn junction causes unusual behavior of G NS. For example, a resonant peak structure appears in G NS reflecting the fact that quasi-bound states are created by the pn junction.