Research

Topological and correlated electronic phases in moiré  materials

Two overlaid atomic lattices can give rise to a moiré superlattice when there is a small rotation in their crystalline axes or a small difference in their lattice constants. The existence of a moiré superlattice significantly modifies the properties of the two combined layers, leading to emerging physical phenomena ranging from Hofstadter's butterfly in graphene/hBN moiré (2013), to unconventional superconductivity in twisted bilayer graphene (2018), and to a fractional Chern insulator in twisted bilayer MoTe2 (2023). A variety of material combinations and twist angle choices constitutes a vast phase space to search for novel quantum phases of matter such as non-abelian fractional Chern insulators, topological superconductivity, quantum spin liquids, etc. 

Bosonic phases in Coulomb-coupled multilayers

Bosons exhibit distinct quantum behaviors from fermions as they are unconstrained by the Pauli exclusion principle. One paradigmatic platform to study ground state bosons is interlayer excitons (electron-hole pairs bound by Coulomb interaction) in two spatially closeby and electrically disconnected layers. This platform uniquely allows easy control of exciton density and direct measurement of the resistance of exciton flow. On this platform, we aim to realize novel states of matter, like exciton superfluid, strongly correlated bosons, and even topological bosons.