4π-Periodic Supercurrent from Surface States in Cd3As2 Nanowire-Based Josephson Junctions
4π-Periodic Supercurrent from Surface States in Cd3As2 Nanowire-Based Josephson Junctions
复制标题
4 基于 Cd3As2 纳米线的约瑟夫森结中来自表面态的 pi 周期超电流
DOI：
10.1103/physrevlett.121.237701
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发表时间：
2018-12-07
影响因子：
8.6
通讯作者：
Yu, Da-Peng
中科院分区：
文献类型：
--
作者：
Wang, An-Qi;Li, Cai-Then;Yu, Da-Peng
狄拉克半金属中超导性和表面态的结合可以在约瑟夫森结组态中产生4 π周期的超导电流，这可以通过奇数Shapiro台阶（特别是n = 1台阶）的缺失来揭示。然而，在普通的2 π周期约瑟夫森效应的高功率振荡机制中，也可以预料到n = 1阶跃的抑制，这与4 π周期超导无关。在这里，为了确定抑制的n = 1步骤的起源，我们进行测量的射频照射在Nb-Dirac半金属Cd 3As 2超导-Nb结连续功率依赖性在各种频率。除了n = 1阶跃抑制外，我们还发现了在n = 0阶跃处第一个节点的残余超电流，这提供了4 π周期超电流的直接和主要特征。此外，通过调节栅极电压，我们可以调制表面和体态的贡献和n = 1步骤的可见性。我们的结果为探索Dirac半金属的拓扑超导性提供了深刻的见解。
The combination of superconductivity and surface states in Dirac semimetal can produce a 4 pi-periodic supercurrent in a Josephson junction configuration, which can be revealed by the missing of odd Shapiro steps (especially the n = 1 step). However, the suppression of the n = 1 step is also anticipated in the high-power oscillatory regime of the ordinary 2 pi-periodic Josephson effect, which is irrelevant to the 4 pi-periodic supercurrent. Here, in order to identify the origin of the suppressed n = 1 step, we perform the measurements of radio frequency irradiation on Nb-Dirac semimetal Cd3As2 nanowire-Nb junctions with continuous power dependence at various frequencies. Besides the n = 1 step suppression, we uncover a residual supercurrent of first node at the n = 0 step, which provides a direct and predominant signature of the 4 pi-periodic supercurrent. Furthermore, by tuning the gate voltage, we can modulate the surface and bulk state contribution and the visibility of the n = 1 step. Our results provide deep insights to explore the topological superconductivity in Dirac semimetals.