Charting Emergent Surface and Bulk States in Correlated Insulators

About This Grant

Non-technical Abstract: This project will widen our understanding of a class of materials known as strongly correlated insulators. Among these materials, some exhibit unusual behaviors, such as having a conducting surface at the boundaries, while the interior remains insulating. Motivated by the decade-long work on a flagship system, samarium hexaboride, this project aims to systematically explore other correlated materials to examine the universality of physical properties. By charting correlated insulators, this project will expand a small set of known examples into a broader class within quantum materials. This work will also be the foundation for correlated insulators to become the platform for future electronics devices. In addition, this project actively trains and engages future students, who will become next-generation scientists. This project also helps military veterans build their foundation and career in the STEM field. Technical Abstract: The research team identifies and characterizes emergent surface states and the true nature of the bulk in correlated insulators. The project's goals are to establish a comprehensive understanding of these materials by asking whether more correlated insulators possess surface states, if their bulk insulation is immune to disorder, and how surface state existence depends on the band gap origin. The scope of the research involves single crystal growth and electrical transport measurements. The primary transport method employs the "inverted resistance" technique, which allows for the detection of the surface states and the characterization of the bulk conductivity hidden under the surface. The research team also uses Corbino disk magnetotransport to further characterize the newly discovered surface states. This approach enables the systematic charting of these materials, leading to a generalization of understanding regarding their unique electronic properties. 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.