论文标题
弹道石墨烯中的Minigap和Andreev绑定状态
Minigap and Andreev bound states in ballistic graphene
论文作者
论文摘要
预测，有限大小的正常导体与超导体耦合相结合，预计将展示出所谓的迷你胶质图，其中禁止进行准粒子激发。在这里，我们报告了对弹道石墨烯中这种小型映射的直接观察，并结合了超导更多的铅。通过有限的偏置光谱通过石墨烯区域的弱耦合连接来探测小型图，其值由设备的尺寸给出。除了微型绘制外，我们还观察到差异电阻中的一个明显峰，我们将其归因于位于超导体 - 透明烯界面附近的弱耦合的Andreev结合状态（ABS）。对于弱磁场，在正常导导区域中累积的相位在定量一致中的ABS与基于Bogolioubov-DE Gennes方程以及分析半经典模型的紧密结合计算的预测转移了ABS。
A finite-size normal conductor, proximity-coupled to a superconductor has been predicted to exhibit a so-called minigap, in which quasiparticle excitations are prohibited. Here, we report on the direct observation of such a minigap in ballistic graphene, coupled to superconducting MoRe leads. The minigap is probed by finite bias spectroscopy through a weakly coupled junction in the graphene region and its value is given by the dimensions of the device. Besides the minigap, we observe a distinct peak in the differential resistance, which we attribute to weakly coupled Andreev bound states (ABS) located near the superconductor-graphene interface. For weak magnetic fields, the phase accumulated in the normal-conducting region shifts the ABS in quantitative agreement with predictions from tight-binding calculations based on the Bogolioubov-de Gennes equation as well as with an analytical semiclassical model.
