SU(4) chiral spin liquid, exciton supersolid and electric detection in moire bilayers

We propose moire bilayer as a platform where exotic quantum phases can be stabilized and electrically detected. Moire bilayer consists of two separate moire superlattice layers coupled through the inter-layer Coulomb repulsion. In the small distance limit, an SU(4) spin can be formed by combining layer pseudospin and the real spin. As a concrete example, we study an SU(4) spin model on triangular lattice in the fundamental representation. By tuning a three-site ring exchange term K similar to t(3)/U-2, we find SU(4) symmetric crystallized phase and an SU(4)(1) chiral spin liquid (CSL) at the balanced filling. We also predict two different exciton supersolid phases with inter-layer coherence at imbalanced filling under displacement field. Especially, the system can simulate an SU(2) Bose-Einstein-condensation (BEC) by injecting inter-layer excitons into the magnetically ordered Mott insulator at the layer polarized limit. Smoking gun evidences of these phases can be obtained by measuring the pseudo-spin transport in the counter-flow channel.

Automated summary

The paper proposes using moire bilayers as a platform to stabilize and detect exotic quantum phases. In the small distance limit, an SU(4) spin can be formed by combining layer pseudospin and real spin. By tuning a ring exchange term K, different phases including symmetric crystallized phase, chiral spin liquid, and exciton supersolid phases can be predicted. Evidences of these phases can be obtained by measuring pseudo-spin transport in the counter-flow channel.