Topological superconductivity in a van der Waals heterostructure
Topological superconductivity in a van der Waals heterostructure
复制标题
DOI：
10.1038/s41586-020-2989-y
复制
发表时间：
2020-12-17
期刊：
影响因子：
64.8
通讯作者：
Liljeroth, Peter
中科院分区：
文献类型：
--
作者：
Kezilebieke, Shawulienu;Huda, Nurul;Liljeroth, Peter
奇特的状态，如拓扑绝缘体、超导体和量子自旋液体，通常是具有挑战性的，或者不可能在单一材料中创建（1-3）。例如，目前尚不清楚拓扑超导性是否存在于任何自然存在的材料中，而拓扑超导性已被认为是拓扑量子计算的关键成分（4-9）。这个问题可以通过刻意选择异质结构中的材料组合来避免，这样不同成分之间的相互作用就会产生所需的物理效果（1,10-15）。在这里，我们使用这种设计方法来制造结合二维（2D）铁磁体和超导体的范德华异质结构，并在系统中观察到二维拓扑超导性。我们使用分子束外延在超导二硒化铌上生长铁磁性三溴化铬（16）的二维岛。然后，我们使用低温扫描隧道显微镜和光谱学来揭示一维马约拉纳边缘模式的特征。制造的二维范德华异质结构提供了一个高质量，可调谐的系统，可以很容易地集成到使用拓扑超导的器件结构中。层状异质结构可以很容易地通过各种外部刺激进入，潜在地允许通过电（17）、机械（18）、化学（19）或光学手段（20）对二维拓扑超导性进行外部控制。
Exotic states such as topological insulators, superconductors and quantum spin liquids are often challenging or impossible to create in a single material(1-3). For example, it is unclear whether topological superconductivity, which has been suggested to be a key ingredient for topological quantum computing, exists in any naturally occurring material(4-9). The problem can be circumvented by deliberately selecting the combination of materials in heterostructures so that the desired physics emerges from interactions between the different components(1,10-15). Here we use this designer approach to fabricate van der Waals heterostructures that combine a two-dimensional (2D) ferromagnet with a superconductor, and we observe 2D topological superconductivity in the system. We use molecular-beam epitaxy to grow 2D islands of ferromagnetic chromium tribromide(16) on superconducting niobium diselenide. We then use low-temperature scanning tunnelling microscopy and spectroscopy to reveal the signatures of one-dimensional Majorana edge modes. The fabricated 2D van der Waals heterostructure provides a high-quality, tunable system that can be readily integrated into device structures that use topological superconductivity. The layered heterostructures can be readily accessed by various external stimuli, potentially allowing external control of 2D topological superconductivity through electrical(17), mechanical(18), chemical(19) or optical means(20).