Interfaces of heterostructures lay the foundation of modern electronic and optical devices, including diodes, transistors, and semiconducting lasers. Atomically-defined interfaces simultaneously offer an ideal platform for studying emergent quantum properties absent in the constituent layers. These unique properties enable novel functionalities that are challenging to achieve in conventional semiconducting devices. I will illustrate the capability of such heterostructure engineering by taking two examples. First, I will explain our discovery of a versatile method for synthesizing ferroelectric materials from non-ferroelectric two-dimensional (2D) materials: by physically stacking two monolayer boron nitrides at controlled angles, novel types of ferroelectricity emerge at the interface. I will demonstrate its functionality as one of the world’s thinnest ferroelectric non-volatile memories at room temperature. Furthermore, I will demonstrate the versatile spintronic functionalities for energy-efficient computation using heterostructures of magnetic topological insulators. Finally, I will conclude by discussing how we can utilize the heterostructure engineering techniques for the future design of quantum materials and functionalities.

Kenji Yasuda is a postdoctoral associate in the Department of Physics at the Massachusetts Institute of Technology, where he investigates artificial ultrathin ferroelectrics in van der Waals heterostructures. He received his Ph.D. in Applied Physics in 2018 from the University of Tokyo, where he grew magnetic topological insulator thin films by molecular beam epitaxy and discovered various spintronic functionalities. He has received several prestigious awards for his graduate and postdoctoral works, including Springer Theses Prize and MRS Postdoctoral Awards. Kenji aims to integrate his previous experiences to design novel quantum properties and functionalities in heterostructures.