近日，美国康奈尔纳米科学Kavli研究所的Kin Fai Mak&Jie Shan及其研究团队取得一项新进展。经过不懈努力，他们证实近藤击穿开始时铁磁性的出现。相关研究成果已于2024年9月9日在国际知名学术期刊《自然—物理学》上发表。
该研究团队报道了通过结合磁输运与光学研究，在MoTe2/WSe2莫尔双层中观察到的密度调控的近藤击穿现象。在临界密度下，研究人员观测到了从重费米液体到绝缘体的转变，以及几乎同时出现的铁磁序。这一观测结果与铁磁安德森绝缘体的出现以及临界密度以下近藤屏蔽效应的抑制相一致。这项研究结果为在莫尔近藤晶格中实现其他量子相变提供了途径。
据悉，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引发了丰富的量子物质相，包括具有重度重整化电子准粒子的费米液体、量子临界非费米液体金属以及非常规超导体。近期对莫尔近藤晶格的展示，为研究具有连续可调参数的近藤问题提供了契机。尽管已经识别出了重费米液体相，但在莫尔近藤晶格中，磁性相仍有待探索。
附：英文原文
Title: Emergence of ferromagnetism at the onset of moiré Kondo breakdown
Author: Zhao, Wenjin, Shen, Bowen, Tao, Zui, Kim, Sunghoon, Knppel, Patrick, Han, Zhongdong, Zhang, Yichi, Watanabe, Kenji, Taniguchi, Takashi, Chowdhury, Debanjan, Shan, Jie, Mak, Kin Fai
Issue&Volume: 2024-09-09
Abstract: 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.
DOI: 10.1038/s41567-024-02636-4
Source: https://www.nature.com/articles/s41567-024-02636-4