6 papers
Topological Charge-Transfer Excitons
Huiyuan Zheng, Kaijie Yang, Ting Cao +1
Excitons possess internal structure absent from single-particle Bloch particles, allowing their band topology to emerge from the bound-state structure rather than being inherited f…
Electrically Programmable Correlated Topology and Magnetism in a Moiré Trilayer
Christiano Wang Beach, Courtney Baier, Kaijie Yang +15
Strong electron-electron interactions underlie a wide range of quantum many-body phenomena, including magnetism, superconductivity, and charge fractionalization. A central goal is…
Giant and Helical Exciton Dipole from Berry Curvature in Flat Chern Bands
Kaijie Yang, Huiyuan Zheng, Xiaodong Xu +2
We show that excitons forming between moiré flat Chern bands possess a substantial electric dipole moment comparable to the moiré lattice parameter times the elementary charge ($…
Single-pair charge-2 Weyl-Dirac composite semimetals
Hui-Jing Zheng, Ke-Xin Pang, Yun-Yun Bai +2
The Nielsen--Ninomiya theorem requires that the total topological chiral charges in a crystal vanish, a constraint typically satisfied by identical nodes like Weyl--Weyl pairs. Whe…
Layer Coherence Origin of Planar Hall Effect: from Charge to Multipole and Valley
Huiyuan Zheng, Dawei Zhai, Cong Xiao +1
We uncover a new origin of the planar Hall effect - as an intrinsic property of layer coherent electrons - that exists even in bilayer and trilayer atomically thin limit. It reform…
Förster valley-orbit coupling and topological lattice of hybrid moiré excitons
Huiyuan Zheng, Ci Li, Hongyi Yu +1
Hybrid exciton in moiré superlattices of two-dimensional (2D) semiconductors inherits the electric dipole, strong moiré trapping, and stacking optical selection rules from its in…