Jennifer Cano, an assistant professor in the College of Arts and Sciences Department of Physics and Astronomy, was part of a team of U.S. and European physicists that has demonstrated a new method for predicting whether metallic compounds are likely to host topological states that arise from strong electron interactions.
Physicists from Rice University — leading the research and collaborating with Cano and physicists from Austria’s Vienna University of Technology (TU Wien), Los Alamos National Laboratory, Spain’s Donostia International Physics Center and Germany’s Max Planck Institute for Chemical Physics of Solids — unveiled their new design principle in a study published online in Nature Physics.
“The landscape of strongly correlated topological matter is both large and largely uninvestigated,” said study co-author Qimiao Si, Rice’s Harry C. and Olga K. Wiess Professor of Physics and Astronomy. “We expect this work will help guide its exploration.”
Si and Cano led a group of theorists that developed a framework for identifying promising candidate materials by cross-referencing information in a database of known materials with the output of theoretical calculations based on realistic crystal structures. Using the method, the group identified the crystal structure and elemental composition of three materials that were likely candidates for hosting topological states arising from the Kondo effect.
“Since we developed the theory of topological quantum chemistry, it has been a longstanding goal to apply the formalism to strongly correlated materials,” said Cano, an assistant professor of physics and astronomy at Stony Brook and research scientist at the Flatiron Institute’s Center for Computational Quantum Physics. “Our work is the first step in that direction.”
Si said the predictive theoretical framework stemmed from a realization he and Cano had following an impromptu discussion session they organized between their respective working groups at the Aspen Center for Physics in 2018.
“What we postulated was that strongly correlated excitations are still subject to symmetry requirements,” he said. “Because of that, I can say a lot about the topology of a system without resorting to ab initio calculations that are often required but are particularly challenging for studying strongly correlated materials.”
To test the hypothesis, the theorists at Rice and Stony Brook carried out model studies for realistic crystalline symmetries. Theoretical teams in Texas and New York had extensive virtual discussions with the experimental group at TU Wien. The collaboration developed the design principle for correlated topological-semimetal materials with the same symmetries as used in the model studied. The utility of the design principle was demonstrated by the TU Wien team, which made one of the three identified compounds, tested it and verified that it hosted the predicted properties.
“All indications are that we have found a robust way to identify materials that have the features we want,” Si said.
Cano, a theoretical physicist studying condensed matter theory, received a 2019 CAREER Award from the National Science Foundation for her project, “Topological crystalline insulators and semimetals: Beyond the bulk-edge correspondence.”