用于量子电路和量子比特的空气稳定单层超导薄膜的封装外延生长
Encapsulation epitaxy of air-stable monolayer superconducting films for quantum circuits and qubits
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- Massachusetts Institute of Technology（麻省理工学院）
- Yale University（耶鲁大学）
- Harvard University（哈佛大学）
- Pohang University of Science and Technology（浦项科技大学）
- New York University（纽约大学）
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中文总结 AI 辅助
本文提出“封装外延”机制，利用石墨烯或hBN封装层在三维衬底上生长空气稳定的大面积单层NbSe2超导薄膜，其具有超导电性和高动力学电感，可用于超导量子电路与量子比特的制造。
中文摘要 AI 辅助
二维（2D）超导体是强关联物理和量子信息科学的新兴平台。其降低的维度、原子级平整的界面和高结晶度对于在超导电路中实现紧凑的集总元件器件具有吸引力。然而，由于二维超导体易受氧化影响，合成大面积、单层二维超导体仍然具有挑战性。在此，我们报道了一种“封装外延”机制，该机制能够生长大面积、空气稳定的单层超导NbSe2薄膜，并探索其在超导量子电路中的应用。预沉积在三维衬底（如SiO2或Si3N4）上的二维封装层（如石墨烯或六方氮化硼（hBN）），既作为其下方单层NbSe2（1L-NbSe2）外延生长的模板，又作为保护覆盖层。该方法制备出均匀、大面积（>1英寸）的1L-NbSe2，其环境稳定性显著增强，使得器件可以在空气中制造。所得的1L-石墨烯/NbSe2异质结构表现出稳健的超导电性（Tc ~ 1 K）和增强的电荷密度波序（TCDW ~ 177 K），表明材料质量高。我们进一步利用无氧化转移和超导边缘接触技术将1L-NbSe2集成到超导电路中。1L-NbSe2表现出测量的动力学电感LK ~ 0.7 nH/方，使其适用于需要高动力学电感元件的量子电路。因此，封装外延为空气稳定的二维超导体和范德华异质结构提供了一条途径，并具有晶圆级单片制造超导量子电路的潜力。
英文摘要
Two-dimensional (2D) superconductors are an emerging platform for strongly correlated physics and quantum information science. Their reduced dimensionality, atomically flat interfaces, and high crystallinity are attractive for realizing compact lumped-element devices in superconducting circuits. However, synthesizing large-area, monolayer 2D superconductors remains challenging because of their susceptibility to oxidation. Here, we report an "encapsulation epitaxy" mechanism that enables the growth of large-area, air-stable, monolayer superconducting NbSe2 films and explore their use in superconducting quantum circuits. A 2D encapsulation layer, such as graphene or hexagonal boron nitride (hBN), pre-deposited on a 3D substrate (e.g., SiO2 or Si3N4), serves both as a template for epitaxial growth of monolayer NbSe2 (1L-NbSe2) underneath it and as a protective cover. This approach produces uniform, large-area (>1-inch) 1L-NbSe2 with greatly enhanced ambient stability, enabling device fabrication in air. The resulting 1L-graphene/NbSe2 heterostructures exhibit robust superconductivity (Tc ~ 1 K) and enhanced charge density wave order (TCDW ~ 177 K), indicative of high material quality. We further integrate 1L-NbSe2 into superconducting circuits using oxidation-free transfer and superconducting edge-contact techniques. The 1L-NbSe2 exhibits a measured kinetic inductance LK ~ 0.7 nH/square, making it suitable for quantum circuits requiring high-kinetic-inductance elements. Encapsulation epitaxy thus provides a route to air-stable 2D superconductors and van der Waals heterostructures, with potential for wafer-scale, monolithic fabrication of superconducting quantum circuitry.
