OBSERVATION OF ANDREEV REFLECTION ENHANCED SHOT NOISE
OBSERVATION OF ANDREEV REFLECTION ENHANCED SHOT NOISE
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DOI：
10.1103/physrevlett.79.3486
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发表时间：
1997-09
影响因子：
8.6
通讯作者：
P. Dieleman;H. Bukkems;T. Klapwijk;M. Schicke;K. Gundlach
中科院分区：
文献类型：
--
作者：
P. Dieleman;H. Bukkems;T. Klapwijk;M. Schicke;K. Gundlach
我们通过实验研究了 NbN/MgO/NbN 超导体-绝缘体-超导体隧道结中的准粒子散粒噪声。观察到的散粒噪声明显大于理论预期。我们将此归因于 MgO 势垒中存在的针孔中发生了多个 Andreev 反射过程。这种机制导致电流以大电荷量子（Andreev 簇）流动，电压相关平均值 m 近似为电子电荷的 1 + 2 Delta/eV 倍。由于这种电荷增强效应，散粒噪声增加了 m 倍。
We have experimentally investigated the quasiparticle shot noise in NbN/MgO/NbN superconductor-insulator-superconductor tunnel junctions. The observed shot noise is significantly larger than theoretically expected. We attribute this to the occurrence of multiple Andreev reflection processes in pinholes present in the MgO barrier. This mechanism causes the current to flow in large charge quanta (Andreev clusters), with a voltage dependent average value of m approximate to 1 + 2 Delta/eV times the electron charge. Because of this charge enhancement effect, the shot noise is increased by the factor m.