Xi Wang’s lab utilizes cutting-edge magneto optical and optoelectronic microscopy and spectroscopy to probe and control excitons, electrons, phonons, magnons et al. in quantum materials for applications in quantum simulation and quantum communication.
We currently focus on four primary research directions: (1)Investigating novel moiré-induced exotic properties in twisted 2D layers; (2)Creating unique two-dimensional and mixed-dimensional heterostructures with tailored artificial superlattices; (3)Developing dynamic simulators with in-situ tunability of properties in quantum materials and devices; (4)Exploring advanced quantum optoelectronics based on highly efficient low-dimensional perovskites.
Light-induced Ferromagnetism
Optical excitation as a dynamic tuning knob to help access the rich many-body Hamiltonian of moiré quantum matter. Here is an example showing the tunability of spin–spin interactions between moiré-trapped carriers, resulting in ferromagnetic order in WS2 /WSe2 moiré superlattices (see Nature, 2022).
Intercell Moiré Exciton Complexes
Novel exciton many-body ground states composed of moiré excitons and correlated electron lattices, enabled by unusual quantum confinement in 2D moiré superlattices, is discovered. (see Nat. Mater., 2023)
Moiré Trion
The formation of moiré trions is observed in WSe2/MoSe2 heterostructures with controllable gating conditions. Together with neutral moiré excitons, such system offers a starting point for engineering both bosonic and fermionic many-body effects based on moiré excitons. (see Nat. Nanotechnol., 2021)
Bosonic Mott Insulating States
Strong onsite dipole–dipole interaction in WSe2/WS2 superlattices leads the formation of correlated bosonic states. With the increase of excitation energy, dipole ladder starts to emerge. (see Nat. Phys. 2023)
Strain-optoelectronics
The tuning of lattice structure and symmetry will affect material properties. Cryo-strain will serve as an effective in-situ knob to manipulate the phase diagram.