I am a senior undergraduate student from the University of Michigan 〽️ majoring in Engineering Physics in the College of Engineering. Right now, I am working with Professor Hui Deng in the Physics Department on quantum many-body physics, topological insulators, and floquet engineering in the low dimensional system.

Research Interest

My research aims to characterize and engineer the electronic correlated states in the strongly correlated Moiré system and the exciton-photon strong coupling in the photonic structures. In the Moiré TMD system, we introduce mechanical misalignment of original TMD lattices that interfere with themselves and form period/quasi-period so-called Moiré supperlattice, which modulates the electron wavefunction through a new-fromed Moiré potential. We are studying the exotic electronic states and the states with topological protection from the breaking of symmetries through the formation of Moiré brillouin zone.

Dual Gate Electrical Sample

Correlated Electronic States in Moiré TMDC

To probe and manipulate the electronic states, we are using electrical methods to dope and apply electric field to the system while using optical methdos to study the change in refraction index and photoluminescence from exciton. When the electronic gas reaches certain density, the change in chemical potential does not necessarily further increase the electronic charge density and form the incompressible state in the system. Some of those incompressible states exhibit a strong optical response to the reflectance contrast and change in photoluminescence.

Floquet Engineering For Many-body States

To study and engineer the incompressible states, we are also using pump-probe spectroscopy to study both the time-dynamics and the introduction of meta-stable states into the system. The strength of the pump-probe spectroscopy allows us to resolve the minimal feature that only exists in the femtosecond to picosecond scale. With the energy detuning between the excitonic transition and the pump laser, we can study the floquet engineering to the topological insulators and the topological phases existing in the system. Apart from the study of stongly correlated electronic system through pump-probe, we are also interested in understanding the nature of light-matter interaction: Can light act as real magnetic field? Can ultrafast light mitigate or enhance the interaction in the strongly-correlated system? Those questions can be further understood by studying the Floquet engineering in the NIR, IR ,or THz regime.

Ultralarge optical stark shift. Figure by Lingxiao Zhou in Cavity Floquet engineering

Exciton-polariton and Photonics

In the electronic system, we are looking for electronic bands and electronic band topology. Similarly, in the photonic crystal, we can find the analogy for photons, where we trap photons to form photon bands with a designed energy-momentum dispersion. We can design the photonic bands with nontrivial topological index and strongly couple them to exciton bands, forming topological exciton-polariton.

Because of the bosonic nature of the exciton-polariton, the interaction principle will be different from the electronic interaction. Some examples of the strong interaction in exciton-polaritons are exciton-polariton Bose-Einstein Condensation (BEC), exciton-polariton superfluid, and Bogoliubov modes in exciton-polariton condensate.