Strong interactions and isospin symmetry breaking in a supermoir\'e lattice

TL;DR

This study explores how supermoiré lattices in multilayer heterostructures influence many-body electronic phases, revealing interaction-driven isospin symmetry breaking and potential new quantum states.

Contribution

It demonstrates the impact of supermoiré lattices on isospin symmetry breaking and uncovers phenomena like miniband filling doubling near specific fillings, advancing understanding of correlated phases.

Findings

Observation of numerous incompressible states due to supermoiré lattice effects.

Detection of miniband filling doubling near ν=-2, suggesting new phases.

Supermoiré lattices as a tool for engineering quantum phases.

Abstract

In multilayer moir\'e heterostructures, the interference of multiple twist angles ubiquitously leads to tunable ultra-long-wavelength patterns known as supermoir\'e 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 supermoir\'e-lattice-scale isospin symmetry breaking driven by strong interactions. By using the supermoir\'e lattice occupancy as a probe of isospin symmetry, we observe an unexpected doubling of the miniband filling near $\nu=-2$, possibly indicating a hidden phase transition or normal-state pairing proximal to the superconducting phase. Our work establishes supermoir\'e lattices as a tunable parameter for designing novel quantum phases and an effective tool for unraveling correlated phenomena in moir\'e materials.