Dipole ladders with large Hubbard interaction in a moiré exciton lattice

Heonjoon Park, Jiayi Zhu, Xi Wang, Yingqi Wang, William Holtzmann, Takashi Taniguchi, Kenji Watanabe, Jiaqiang Yan, Liang Fu, Ting Cao, Di Xiao, Daniel R. Gamelin, Hongyi Yu, Wang Yao, Xiaodong Xu

Research output: Contribution to journalArticlepeer-review

32 Scopus citations

Abstract

Two-dimensional semiconductor moiré superlattices have emerged as a powerful platform for engineering correlated electronic phenomena. On the other hand, optical excitation creates charge neutral interlayer excitons with an out-of-plane electric dipole. Strong onsite dipole–dipole interaction promises the formation of correlated bosonic states, akin to the Mott states of electrons, but has not yet been demonstrated. Here we report a large interaction between excitons occupying the same moiré lattice site—characterized by the Hubbard U parameter—and consequent dipole ladders with spin- and electron-filling dependence in WSe2/WS2 moiré superlattices. Photoluminescence measurements show successive peaks emerging with an energy separation of around 34 meV above the ground state as the exciton density is increased. This corresponds to the sequential injection of excitons into a single site with an energy cost to overcome the large exciton Hubbard U, forming a dipole ladder. Based on findings of local magnetic moments at two holes per moiré cell, we show that excitons can also fill a second moiré orbital, establishing the two-orbital nature of the moiré potential landscape. Our results show that the Bose–Hubbard model with possible exciton crystal phases can be investigated in interacting opto-moiré quantum matter.

Original languageEnglish
Pages (from-to)1286-1292
Number of pages7
JournalNature Physics
Volume19
Issue number9
DOIs
StatePublished - Sep 2023

Fingerprint

Dive into the research topics of 'Dipole ladders with large Hubbard interaction in a moiré exciton lattice'. Together they form a unique fingerprint.

Cite this