CAREER: Manipulating Topology and Correlations in 2D Heterostructures by Dynamic Structural Control

Non-Technical Abstract:

The way electricity flows in a material depends on how its atoms are arranged. Normally, the arrangement of atoms is frozen in a crystal pattern that cannot be easily changed. This project studies how to dynamically change the crystal pattern in a material, with the goals of controlling the flow of electricity and understanding its quantum properties.

The specific materials studied are only a few atoms thick, so-called two-dimensional or “2D” materials. 2D materials can be stacked like sheets of paper and the individual sheets can easily slide and rotate, which changes the internal crystal pattern. The research team is developing techniques to rapidly modify the crystal pattern in a 2D material stack so that the effects on electricity flow can be studied.

These studies will be performed in a cryogenic refrigerator at temperatures near absolute zero where the quantum behavior of the electrons carrying the electricity is more apparent. The success of this project will advance knowledge of quantum electrical properties which is key to developing new electronic technologies for computers and wireless communication.

This research project will go hand-in-hand with an educational mission focused on mentoring students, increasing participation of students from underrepresented minorities, and public outreach by science demos and physics-based video games. Technical Abstract:

Heterostructures of 2-dimensional (2d) materials exhibit a wide range of electronic phenomena that depend sensitively on the physical structure of internal twisted interfaces. The research team has developed techniques to dynamically modify the physical structure of 2d material devices in-situ that are enabled by the low friction sliding between 2d layers.

This project proposes to apply these dynamic structural control techniques to (1) investigate dynamic electronic effects that arise from sliding moiré superlattices, and (2) systematically study correlated and topological physics of multi-moiré systems by in-situ control of twist angle and layer displacement. The successful outcome of this research would lead to the development of topological charge pumps for manipulating electrons in insulators, as well as a deeper understanding of how moirés can modify electronic behaviors.

The research project will provide a foundation for educational activities focused on training students as independent scientists. The principal investigator will implement a codified Ph.D. curriculum that prepares students for diverse career opportunities, with an emphasis on both technical skills, such as nanofabrication and programming, as well as soft skills, such as management and communication.

This training program will serve as a venue for increasing the participation of students who are underrepresented in STEM. Furthermore, this activity includes multiple approaches to increasing public engagement in the sciences, including a high school science summer program, the distribution of quantum materials demos to elementary school students, and the development of physics-based video games.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.