美国哈佛大学Amir Yacoby团队近日研究了超微晶格中的强相互作用和同位旋对称性破缺。该研究于2025年7月3日发表在《科学》杂志上。

在多层莫尔异质结构中，多个扭转角的干涉普遍导致可调谐的超长波长模式，即超莫尔晶格。然而，它们对系统的多体电子相图的影响在很大程度上仍未被探索。

研究组提出了局部可压缩性的测量结果，揭示了由强相互作用驱动的超莫尔-晶格尺度同位旋对称性破缺所导致的许多不可压缩状态。通过将超晶格占据作为同位旋对称的探测，研究组观察到ν=2附近的迷你带填充出乎意料地加倍，这可能表明在超导相附近有一个隐藏的相变或正常状态配对。该工作建立了超微晶格作为设计量子相的可调参数和揭示微晶格材料中相关现象的有效工具。

附：英文原文

Title: Strong interactions and isospin symmetry breaking in a supermoiré lattice

Author: Yonglong Xie, Andrew T. Pierce, Jeong Min Park, Daniel E. Parker, Jie Wang, Patrick Ledwith, Zhuozhen Cai, Kenji Watanabe, Takashi Taniguchi, Eslam Khalaf, Ashvin Vishwanath, Pablo Jarillo-Herrero, Amir Yacoby

Issue&Volume: 2025-07-03

Abstract: In multilayer moiré heterostructures, the interference of multiple twist angles ubiquitously leads to tunable ultra-long-wavelength patterns known as supermoiré lattices. However, their impact on the system’s many-body electronic phase diagram remains largely unexplored. We present local compressibility measurements revealing numerous incompressible states resulting from supermoiré-lattice-scale isospin symmetry breaking driven by strong interactions. By using the supermoiré lattice occupancy as a probe of isospin symmetry, we observe an unexpected doubling of the miniband filling near ν=2, possibly indicating a hidden phase transition or normal-state pairing proximal to the superconducting phase. Our work establishes supermoiré lattices as a tunable parameter for designing quantum phases and an effective tool for unraveling correlated phenomena in moiré materials.

DOI: adl2544

Source: https://www.science.org/doi/10.1126/science.adl2544