Sliding ferroelectricity via van der Waals engineering
Name
wang-xrwang-phd-physics-2026-thesis.pdf
Size
53.18 MB
Format
Adobe PDF
Checksum (MD5)
cebb3d820517164bc8564971c67f03a4
Author(s)
Wang, Xirui
Advisor(s)
Jarillo-Herrero, Pablo
Date Issued
February 2026
Publisher
Massachusetts Institute of Technology
Abstract
The discovery of graphene two decades ago opened a new era in condensed matter physics by enabling the isolation of a single atomic layer from a bulk crystal. These layers can then serve as building blocks to assemble new materials with properties absent in the individual layers, which is the essence of van der Waals engineering. In this thesis, I use this technique to engineer a series of atomically thin ferroelectrics, where the individual constituents are non-ferroelectric van der Waals crystals. Unlike conventional ferroelectrics, where ionic motion dominates the switching behavior, here the switching arises from interlayer sliding motion, namely sliding ferroelectricity. In the first part, I show that by controlling the stacking order, a bilayer boron nitride can be made ferroelectric, confirmed by piezoresponse force microscopy and transport measurements using graphene as an electronic sensor. Next, I apply this design principle to four transition metal dichalcogenide semiconductors. Such van der Waals interlayer sliding motion enables nanosecond switching speed and high endurance in device performance. Lastly, by twisting two monolayers of boron nitride at a small angle, I generate a moiré polar substrate for engineering the electronic band structure of a target layer. In the future, advances in reliable methods for probing polarization, together with ultrafast electrical and optical techniques, will enable deeper understanding and more effective control of sliding ferroelectricity. Continued progress in fabrication will improve endurance, controllability, and scalability. Finally, expanding the material family, particularly by integrating ferroelectricity with other quantum degrees of freedom, will open the way to new functional materials based on van der Waals ferroelectricity.
MIT Department
Massachusetts Institute of Technology. Department of Physics
Terms of Use
In Copyright - Educational Use Permitted
Copyright retained by author(s)
Persistent DSpace Link
