Research

We are particularly interested in novel quantum phases driven by topology, correlations or both. The concept of topological quantum matter generalizes the physics behind quantum Hall effects and allows for quantized and protected electron transport at zero magnetic field; With the help of electron correlations, a single electron added to a many-electron system can effectively split itself into parts ("partons"), creating fractionalized particles with exotic properties. In addition to their fundamentally interesting physics, some kinds of these exotic particles, especially when their states are topologically protected, can be used to shape our future technologies. They might be critical in the future for us to manipulate energy and information at the quantum level.

In our lab, we create/search for correlated and topological quantum states in two-dimensional crystals and structures. They often resides in new types of electronic phases, such as new types of superconductors, insulators or magnets. We are also interested in developing quantum device applications based on the observed phenomena. 

We employ and develop a series of experimental techniques to address  challenges in creating, understanding and utilizing the emergent quantum phenomena. Nanofabrication techniques are used to assemble designated structures and define devices. The properties of the electronic quantum states are characterized and controlled by both electronic techniques and optical spectroscopic / microscopic tools. We are interested in developing measurement techniques for devices subject to various conditions, including ultralow temperatures, high magnetic fields, high pressures and ultrafast laser radiation.

Our sponsors.

An interesting example is monolayer transition metal dichalcogenides with 1T' or 1Td lattice structure. In particular, monolayer WTe2 is one such material. It is a large-gap quantum spin Hall insulator whose edge hosts a helical mode (read more). Moreover, electrostatic doping (to electron densities > 5 × 1012 cm-2) converts the monolayer into a superconductor with Tc up to ~1 Kelvin (read more). The figure sketches the electronic phase diagram of the monolayer. These observations create new opportunities in engineering novel topological and correlated quantum states, including topological superconductivity and Majorana modes. They also suggest fascinating possibilities offered by monolayer crystals, of which WTe2 is just one member in the large family.