Time:  09:00am  (UTC/GMT+8:00, Beijing/Shanghai), Sep. 23, 2021

Meeting URL:  https://us06web.zoom.us/j/9495597503?pwd=UFVMUUVxb3pDUHRkWEFQY3MzRjJYUT09

Zoom Meeting ID: 949 559 7503

Password: 2021

Speaker: Ya-Hui Zhang (Harvard)

Abstract:

We propose moiré bilayer as a platform where exotic quantum phases can be stabilized and electrically detected. Moiré bilayer consists of two separate moiré 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 , 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) BoseEinstein-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

About the speaker：

Ya-Hui Zhang got his PhD at MIT, supervised by Prof. T.Senthil. He is a postdoc at Harvard university, advised by Prof. Ashvin Vishwanath and Prof. Subiar Sachdev. His research interest is on strongly correlated systems, including cuprate, quantum Hall system, and moire system.

Invited by Prof. Zheng Zhu