Research

Designer flat-band systems in 2D materials and thin films

The minimal energy dispersion of flat bands leads to a variety of exotic electronic states and collective phenomena driven by strong electron correlation. A pivotal milestone in condensed matter physics is the advent of twistronics, where the moiré structure profoundly alters the energy landscape in materials by introducing the moiré lengthscale. An alternative approach is to create lattice-driven flat-band systems, wherein specifically designed lattice geometry can lead to highly localized electronic states with minimal dispersive band structure. In our lab, we plan to combine atomic-layer-by-layer growth with MBE and precise interlayer control with vdW stacking to create designer flat-band systems, and study their electronic states influenced by electron-electron interaction and non-trivial topology with STM.

Exotic magnetic ground states in magnetic thin films and heterostructures

Magnetism in 2D materials is an exciting topic. Rich magnetic ground states can be found due to competing magnetic interactions and enhanced fluctuations, and their magnetic structures can be highly tunable through controlled stacking, twisting, and electrostatic gating. These magnets are also a key ingredient in vdW heterostructures, where novel quasiparticles such as magnetic skyrmions and 1D Majorana modes can emerge. We will combine MBE synthesis, vdW stacking, and spin-polarized STM to explore exotic magnetic ground states in these magnetic materials and heterostructures to examine their magnetic properties with atomic precision.

Engineering and controlling spin states in quantum defects

Spin defects in solid-state systems are becoming increasingly important due to their potential for quantum sensing, communication, and computation. Realizing their full potential, however, requires precise placement of their spatial location, improved control over their electronic states, and accurate characterization of their coherent behavior. STM provides an ideal tool that satisfies all these requirements by manipulating and studying these spin defects one atom at a time. We will use the surface of vdW materials as a platform to create, engineer, and understand the coherent behavior of various spin defects with STM, and explore their potential application in quantum information science.