In the Kondo lattice model, the interaction of a lattice of localized magnetic moments with a sea of conduction electrons induces rich quantum phases of matter, including Fermi liquids with heavily renormalized electronic quasiparticles, quantum critical non-Fermi liquid metals and unconventional superconductors. The recent demonstration of moiré Kondo lattices has presented an opportunity to study the Kondo problem with continuously tunable parameters. Although a heavy Fermi liquid phase has been identified, the magnetic phases remain unexplored in moiré Kondo lattices. Here we report a density-tuned Kondo breakdown in MoTe₂/WSe₂ moiré bilayers by combining magnetotransport and optical studies. At a critical density, we observe a heavy Fermi liquid to insulator transition and a nearly concomitant emergence of ferromagnetic order. The observation is consistent with the emergence of a ferromagnetic Anderson insulator and suppression of the Kondo screening effect below the critical density. Our results suggest a path for realizing other quantum phase transitions in moiré Kondo lattices.

在近藤晶格模型中，局域磁矩晶格与传导电子海的相互作用诱发了丰富的物质量子相，包括具有高度重整化电子准粒子的费米液体、量子临界非费米液态金属和非常规超导体。最近近藤莫尔晶格的演示为研究具有连续可调参数的近藤问题提供了机会。尽管重费米液相已被识别，但莫尔近藤晶格中的磁性相仍未被探索。在这里，我们通过结合磁输运和光学研究，报告了 MoTe ₂ /WSe ₂莫尔双层中密度调谐的 Kondo 击穿。在临界密度下，我们观察到重费米液体到绝缘体的转变以及几乎同时出现的铁磁序。该观察结果与铁磁安德森绝缘体的出现以及近藤屏蔽效应被抑制到低于临界密度是一致的。我们的结果提出了一条在近藤莫尔晶格中实现其他量子相变的途径。