Low Temperature Laboratory, Aalto University, P.O. Box 13500, 00076 Aalto, Finland.
Phys Rev Lett. 2011 May 27;106(21):217003. doi: 10.1103/PhysRevLett.106.217003. Epub 2011 May 25.
We provide a direct proof of two-electron Andreev transitions in a superconductor-normal-metal tunnel junction by detecting them in a real-time electron counting experiment. Our results are consistent with ballistic Andreev transport with an order of magnitude higher rate than expected for a uniform barrier, suggesting that only part of the interface is effectively contributing to the transport. These findings are quantitatively supported by our direct current measurements in single-electron transistors with similar tunnel barriers.
我们通过实时电子计数实验检测到超导-正常金属隧道结中的双电子安德烈夫跃迁，从而提供了一个直接的证明。我们的结果与弹道安德烈夫输运一致，其速率比均匀势垒预期的高一个数量级，这表明只有部分界面有效地参与了输运。我们在具有类似隧道势垒的单电子晶体管中的直流测量结果定量地支持了这些发现。
