应变图案化石墨烯中的涌现阻挫磁性
Emergent frustrated magnetism in strain-patterned graphene
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- National Cheng Kung University（国立成功大学）
- University of Wisconsin-Madison（威斯康星大学麦迪逊分校）
- University of Antwerp（安特卫普大学）
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中文总结 AI 辅助
本研究通过光刻应变工程在石墨烯中产生赝磁场超晶格，实现关联电子系统，观察到阻挫磁性及输运异常，为范德华材料中平带和量子态调控提供可扩展途径。
中文摘要 AI 辅助
几何阻挫磁性传统上源于晶格上预先存在的磁矩，而晶格的几何结构使得这些磁矩之间的相互作用无法同时得到满足，从而产生高度简并的态和丰富的集体行为。在本质上非磁性的材料中创造这种阻挫则提出了一个根本不同的挑战，要求磁性以及相互竞争的作用都从关联电子中涌现。在这里我们表明，这可以通过光刻可编程的应变工程在石墨烯中实现。将应变及相关的赝磁场（PMF）图案化为超晶格，会创建一个具有平带和强相互作用的关联电子系统。输运测量揭示了相互作用驱动的绝缘行为、各向异性磁滞以及让人联想到自旋冻结的缓慢弛豫动力学，这些现象被PMF定义的红宝石超晶格上竞争磁矩的蒙特卡洛模拟定性捕获。低温磁力显微镜进一步揭示了与PMF景观相关的磁纹理。这些观察证明了在原本非磁性的石墨烯中从关联电子涌现出的阻挫磁性。我们的结果确立了光刻应变工程作为范德华材料中平带和关联态的一种通用且可扩展的途径，为可编程量子物质提供了一个多功能平台。
英文摘要
Geometrically frustrated magnetism conventionally arises from pre-existing magnetic moments on lattices whose geometry prevents their interactions from being simultaneously satisfied, giving rise to highly degenerate states and rich collective behavior. Creating such frustration in an intrinsically non-magnetic material presents a fundamentally different challenge, requiring both the magnetism and the competing interactions to emerge from correlated electrons. Here we show that this can be realized in graphene through lithographically programmable strain engineering. Patterning strain and the associated pseudo-magnetic field (PMF) into superlattices creates a correlated electronic system with flat bands and strong interactions. Transport measurements reveal interaction-driven insulating behavior, anisotropic magnetic hysteresis, and slow relaxation dynamics reminiscent of spin freezing, qualitatively captured by Monte Carlo simulations of competing magnetic moments on the PMF-defined ruby superlattice. Cryogenic magnetic force microscopy further reveals magnetic textures associated with the PMF landscape. These observations demonstrate frustrated magnetism emerging from correlated electrons in otherwise non-magnetic graphene. Our results establish lithographic strain engineering as a general and scalable route to flat bands and correlated states in van der Waals materials, providing a versatile platform for programmable quantum matter.
