Superconductivity in the Surface State of Noble Metal Gold and its Fermi Level Tuning by EuS Dielectric.
Superconductivity in the Surface State of Noble Metal Gold and its Fermi Level Tuning by EuS Dielectric.
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DOI：
10.1103/physrevlett.122.247002
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发表时间：
2019-02
影响因子：
8.6
通讯作者：
P. Wei;S. Manna;M. Eich;P. Lee;J. Moodera
中科院分区：
文献类型：
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作者：
P. Wei;S. Manna;M. Eich;P. Lee;J. Moodera
具有强Rashba自旋轨道耦合的鲁棒且可扩展的量子材料中的诱导超导性（SC）对于产生拓扑超导性和马约拉纳束缚态（MBS）特别有吸引力。金（111）薄膜由于具有较大的Rashba能量、预测的拓扑性质以及大规模制备MBS器件的可能性而被认为是一种有希望的候选材料。我们的实验证明了实现这一目标的两个重要步骤。我们成功地证明了在外延钒膜上生长的外延Au（111）层的Shockley表面态（SS）中的诱导SC，这在晶片级上是容易实现的。SC的出现在SS，这是物理上分离的大块超导体，是通过间接准粒子散射过程，而不是通过传统的界面Andreev反射。我们进一步展示了通过将SS与高介电常数的铁磁绝缘体EuS相连接来调节SS费米能级（E_{F}）的能力。超导SS中的E_{F}从1550 mV移到134 mV是在该鲁棒系统中实现MBS的重要一步。
The induced superconductivity (SC) in a robust and scalable quantum material with strong Rashba spin-orbit coupling is particularly attractive for generating topological superconductivity and Majorana bound states (MBS). Gold (111) thin film has been proposed as a promising candidate because of the large Rashba energy, the predicted topological nature, and the possibility for large-scale MBS device fabrications. We experimentally demonstrate two important steps towards achieving such a goal. We successfully show induced SC in the Shockley surface state (SS) of ultrathin Au(111) layers grown over epitaxial vanadium films, which is easily achievable on a wafer scale. The emergence of SC in the SS, which is physically separated from a bulk superconductor, is attained by indirect quasiparticle scattering processes instead of by conventional interfacial Andreev reflections. We further show the ability to tune the SS Fermi level (E_{F}) by interfacing SS with a high-κ dielectric ferromagnetic insulator EuS. The shift of E_{F} from ∼550 to ∼34 mV in superconducting SS is an important step towards realizing MBS in this robust system.