My area of interest is low-temperature correlated electron systems. At low temperatures, we can study high-quality systems that exhibit pure electron interactions—such as those found in the quantum Hall effect, superconductivity, and 2D magnetism—with minimal thermal noise.

However, these systems must be measured at extremely low temperatures, and their signals are very small, often at the nanometer scale. To investigate them, we need highly sensitive techniques, such as Scanning Probe Microscopy (SPM), Magneto-Optical Kerr Effect (MOKE) microscopy, nano-patterned transport measurements, and torque magnetometry.

I am particularly excited about the research potential of my SPM project. As its name suggests, Scanning Probe Microscopy relies on the probe. By successfully designing and building this measurement tool, we can measure a variety of physical properties simply by changing the probe. For example, surface topography, conductivity, magnetic order and moment, and resistivity are all significant from a physical standpoint. In particular, measuring magnetic order and moment provides direct insight into strongly correlated electron systems.

Magnetic Force Microscopy (MFM) is one application of SPM. It requires probes that are coated with magnetic material. When such a probe scans the sample at a constant distance in an area dominated by magnetic forces, its motion detects subtle magnetic interactions. This method offers spatial resolution of a few nanometers and height resolution in the sub-nanometer range. Additionally, due to the high Q factor of the probe, it can sensitively detect very weak magnetic properties, such as those in 2D magnets or the vortices of type-II superconductors.

My research focuses on 2D magnets and superconductor junctions. When a 2D magnet is combined with a superconductor, the magnet can influence the electron motion in the superconductor, thereby altering its magnetic order. A Cryogenic MFM (Cryo-MFM) will be an invaluable tool for measuring these correlated electron systems. Furthermore, if even higher sensitivity to magnetic moments is required, I am also considering the application of NV-center-based MFM.