Moehle Christian M, Ke Chung Ting, Wang Qingzhen, Thomas Candice, Xiao Di, Karwal Saurabh, Lodari Mario, van de Kerkhof Vincent, Termaat Ruben, Gardner Geoffrey C, Scappucci Giordano, Manfra Michael J, Goswami Srijit
QuTech and Kavli Institute of Nanoscience, Delft University of Technology, 2600 GA Delft, The Netherlands.
Department of Physics and Astronomy, Purdue University, West Lafayette, Indiana 47907, United States.
Nano Lett. 2021 Dec 8;21(23):9990-9996. doi: 10.1021/acs.nanolett.1c03520. Epub 2021 Nov 18.
Topological superconductivity can be engineered in semiconductors with strong spin-orbit interaction coupled to a superconductor. Experimental advances in this field have often been triggered by the development of new hybrid material systems. Among these, two-dimensional electron gases (2DEGs) are of particular interest due to their inherent design flexibility and scalability. Here, we discuss results on a 2D platform based on a ternary 2DEG (InSbAs) coupled to in situ grown aluminum. The spin-orbit coupling in these 2DEGs can be tuned with the As concentration, reaching values up to 400 meV Å, thus exceeding typical values measured in its binary constituents. In addition to a large Landé g-factor of ∼55 (comparable to that of InSb), we show that the clean superconductor-semiconductor interface leads to a hard induced superconducting gap. Using this new platform, we demonstrate the basic operation of phase-controllable Josephson junctions, superconducting islands, and quasi-1D systems, prototypical device geometries used to study Majorana zero modes.
拓扑超导性可以在与超导体耦合的具有强自旋轨道相互作用的半导体中实现。该领域的实验进展常常由新型混合材料系统的发展所引发。其中，二维电子气（2DEG）因其固有的设计灵活性和可扩展性而备受关注。在此，我们讨论基于与原位生长的铝耦合的三元二维电子气（InSbAs）的二维平台的相关结果。这些二维电子气中的自旋轨道耦合可以通过砷浓度进行调节，达到高达400毫电子伏特·埃的值，从而超过在其二元组分中测得的典型值。除了具有约55的大朗德g因子（与锑化铟相当）外，我们还表明，干净的超导体 - 半导体界面会导致硬诱导超导能隙。利用这个新平台，我们展示了用于研究马约拉纳零模的典型器件几何结构——相位可控约瑟夫森结、超导岛和准一维系统的基本操作。
