From superconductivity to fractionalized particles, fascinating phenomena arise in quantum materials due to the collective behaviors of electrons. These quantum phenomena are not only captivating for physicists, but they also offer significant opportunities for future quantum technologies. In my talk, I will introduce van der Waals (vdW) heterostructures as a rising platform to fabricate new quantum materials. These heterostructures are made by mechanically assembling layers of two-dimensional materials together, breaking through traditional material synthesis limitations and providing new ways to create quantum matter.

During the first part of my talk, I will demonstrate how the interplay between different atomic layers can be leveraged to design unique quantum properties. Specifically, I will focus on graphene double-layers, where interlayer Coulomb interactions are exploited to enable a superfluid condensate of fermion pairs with an adjustable coupling strength. This realization helps us achieve a long-sought paradigm known as BEC-BCS crossover. In the second part, I will discuss our efforts to develop scanning tunneling microscopy (STM) measurements on vdW heterostructures, enabling us to uncover hidden quantum properties and decipher enigmatic quantum states of matter. I will use our experiments on visualizing quantum Hall states to showcase our capabilities and the power of the local probe. Finally, I will conclude by sharing my vision for exploring major themes in condensed matter physics through the integration of different interplays between separate atomic layers.
 

Xiaomeng Liu is a PCCM (Princeton Center for Complex Materials) postdoctoral fellow in Prof. Ali Yazadani's group at Princeton University. He did his undergraduate study at Peking University and obtained his Ph.D. from Harvard University working with Prof. Philip Kim, where he focused on creating new quantum states of matter in heterostructures of two-dimensional materials. His current research is dedicated to using scanning tunneling microscopes to study and understand quantum phenomena in two-dimensional materials. He recently received the 2023 Lee Osheroff Richardson (LOR) Science Prize.

Please contact phweb@ust.hk should you have questions about the talk.