Correlations in Topological Heterostructures
Abstract
In the past 15 years, topological matter has become a major focus of materials physics, resulting in an avalanche of new materials discoveries, such as three-dimensional topological insulators and semimetals. These materials host new phenomena that are generating enormous excitement for new electronic, photonic, spintronic and quantum device applications. Even richer physics is expected when topology acts in concert with strong electron correlations. Electron-electron interactions are, however, weak in most topological and Dirac materials studied to date, due to the vanishing density of states at the point-like nodes. In contrast, flat electronic bands, which are non-dispersive electronic states, have a much higher density of states, and promote strong correlations. The objective of this project to use thin films and heterostructures of known topological materials to controllably engineer such flat band states. Our approach builds on recent progress in epitaxial heterostructures of topological semimetals, such as cadmium arsenide. One approach that will be the focus of this project involves stacking of Dirac nodes that brought into proximity in multilayers. A second approach to flat bands involves non-uniform strain fields, such as those caused by dislocation arrays that form at interfaces between epitaxial layers with different lattice parameters. The periodically varying strain field acts as a pseudomagnetic field, which produces electronic states with a flat energy dispersion. The anticipated outcomes of the project are increased tunability and controllability of topological states of matter and new quantum phases and functionalities that benefit from topological protection.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Mar 07, 2023
- Source ID
- FA95502110180
Entities
People
- Susanne Stemmer
Organizations
- Air Force Office of Scientific Research
- United States Air Force
- University of California, Santa Barbara