AI 中文总结
本文在NbSe₂/CrBr₃异质结构中实现效率达35.7%的无场超导二极管效应，其极性可通过磁场历史编程，源于CrBr₃层状亚铁磁性，为非互易超导性提供新机制。
AI 中文摘要
超导二极管效应（SDE）以非互易无耗散超电流为特征，为超低功耗超导电子学提供了极具前景的路径。然而，多数实现方案需依赖外磁场，在零场下获得大且可控的SDE仍具挑战性。本文报道在范德华NbSe₂/CrBr₃异质结构中实现了效率达35.7%的无场SDE，其极性可通过磁场历史编程调控。与基于有限动量配对的传统机制不同，该SDE源于对称性允许的、库珀对动量奇异性的主导三次项，该项产生不等的临界电流，同时使平衡凝聚体保持零动量。值得注意的是，在垂直磁场扫描时，二极管极性会发生非单调且滞后的反转，这无法用迈斯纳屏蔽或传统铁磁邻近效应解释。结合输运测量、微磁模拟和推广的金兹堡-朗道理论，我们将这些非传统行为归因于CrBr₃中的层状亚铁磁性，其中共存的铁磁与反铁磁层间耦合产生作用于NbSe₂的、依赖历史的界面交换场。本研究揭示了非互易超导性的一种独特机制，并确立层状范德华磁性为高效、可编程无场超导二极管的多功能平台。
英文摘要
The superconducting diode effect (SDE), characterized by nonreciprocal dissipationless supercurrent, offers a promising route toward ultralow-power superconducting electronics. Yet most realizations require an external magnetic field, and achieving a large, controllable SDE at zero field remains challenging. Here we report a field-free SDE with an efficiency reaching 35.7% in a van der Waals NbSe$_2$/CrBr$_3$ heterostructure, whose polarity is programmable by magnetic-field history. Unlike conventional mechanisms based on finite-momentum pairing, the SDE originates from the leading symmetry-allowed cubic term odd in Cooper-pair momentum, which yields unequal critical currents while leaving the equilibrium condensate at zero momentum. Remarkably, upon sweeping a perpendicular magnetic field, the diode polarity undergoes nonmonotonic and hysteretic reversals that cannot be explained by Meissner screening or conventional ferromagnetic proximity. Combining transport measurements, micromagnetic simulations, and a generalized Ginzbur-Landau theory, we attribute these unconventional behaviors to layered ferrimagnetism in CrBr$_3$, where coexisting ferromagnetic and antiferromagnetic interlayer couplings produce a history-dependent interfacial exchange field acting on NbSe$_2$. Our results reveal a distinct mechanism for nonreciprocal superconductivity and establish layered van der Waals magnetism as a versatile platform for high-efficiency, programmable, field-free superconducting diodes.
Comments7 pages, 4 figures
