Moire superlattices emerge when two stacked materials have a slight lattice or angle mismatch, forming interference patterns with enlarged real-space periodicity and reduced bandwidth in momentum space. They have offered a new paradigm for the study of strong electronic correlations, non-trivial band topology, and emergent phenomena. At N08, we build different types of moire superlattices and investigate them from multiple perspectives such as electronic transport and optical spectroscopy. The flat bands and quenched kinetic energy allow us to observe correlated insulating states at fractional fillings in moire heterobilayer WSe₂/WS₂. We have also created moire magnets in twisted bilayer CrI₃ and observed coexisting ferromagnetic and antiferromagnetic ground states, indicating that stacking and angle mismatch can strongly reshape magnetic properties. More recently, we observed trapping and manipulation of Rydberg excitons by moire potentials.

We are working on fabricating high-quality nano-devices based on topological materials and exploring interface engineering. This development aims to facilitate the study of intrinsic transport properties, the role of electron-electron interactions, topological phase transitions, and potential applications in topological electronics and spintronics. Additionally, we explore growth methods for magnetic thin films with topological electronic band structures to reveal transport properties arising from the interplay between topology, magnetism, and strong correlations.

Rydberg excitons are highly excited electron-hole pairs generated through photon excitation in semiconductors. With the development of two-dimensional materials, the study of Rydberg excitons has expanded into the 2D limit. Their solid-state nature, large dipole moments, strong mutual interactions, and enhanced coupling to the surroundings provide opportunities in sensing, quantum optics, and quantum simulation. Their sensitivity to dielectric screening can be used to explore novel quantum states and quantum phase transitions near two-dimensional electronic systems, an approach we pioneered as Rydberg sensing. By using moire potentials in two-dimensional moire superlattices, spatial confinement and manipulation of Rydberg excitons can also be achieved.

We are presently developing an experimental setup that will enable in-situ pressure adjustments for nano-devices constructed from low-dimensional quantum materials. The application of hydrostatic pressure is an effective way to reduce the van der Waals gap between layers and significantly enhance interlayer hybridization.

Materials without inversion symmetry provide an intriguing platform that can host multiple orders and non-trivial topological properties. The interplay between these degrees of freedom leads to rich quantum phenomena that can be captured by low-temperature magneto-transport measurements. One example is the finite-momentum pairing state that has been experimentally verified. Our ongoing project focuses on its possible existence and other unconventional pairing schemes in a variety of van der Waals heterostructures. Symmetry, ferroelectricity, and the Berry phase are treated as key parameters for understanding their experimental signatures.

Our lab has already established a set of advanced experimental facilities capable of van der Waals heterostructure fabrication, nanofabrication, and conducting transport or optical studies at low temperatures and under high magnetic fields. The main equipment in our lab includes:

1. Two dry VTI cryostat (1.5 K- 300 K, 9 T and 16 T).
2. A He3 probe with rotation stage (300 mK, 16 T).
3. An Attodry 2100 cryostat (1.7 K-300 K) with vector magnets (9 T- 3 T), specialized for optical spectroscopy.
4. A Montana cryostat (4 K-300 K) for optical spectroscopy and high-pressure studies.
5. A Park AFM dedicated for high-resolution surface characterization.
6. Three home-built transfer stages (including one in inert atmosphere) for deterministic assembly of van der Waals heterostructures.
7. A 3D printer for for rapid prototyping of custom experimental components.
8. Many more...