Theory-guided Experiments in Search of Designed Topological Insulators and Band-Inverted Insulators

Project Personnel

Alex Zunger

Principal Investigator

University of Colorado at Boulder

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Daniel Dessau

University of Colorado at Boulder

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Gang Cao

University of Kentucky

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Funding Divisions

Division of Materials Research (DMR), Division of Mathematical Sciences (DMS), Office of Multidisciplinary Activities (OMA)

“Topological Insulation" represents a new functionality whereby a specific inversion in the order of the energy bands in a 3D bulk insulator necessitates that the corresponding 2D surface would be metallic, with linearly dispersed crossing surface bands. Most high technologies are based on unique functionalities (conductivity, magnetism) that "live" in certain, specific materials and no others. Identifying, (out of an astronomic number of possibilities) those materials likely to have a specific functionality is a generally unsolved problem in material research. This work offers a general strategy around this problem. It focuses on a newly discovered functionality- a single material having a conducting surface but an insulating interior, a property called "Topological Insulation" (TI). By combining a calculable "metric" (based on quantum theory of matter) that guesses if a material is likely to be a TI or not, with laboratory synthesis and synchrotron measurement, we offer to identify hitherto unknown new materials that have such prescribed properties. This project can lead to next-generation wide gap, light element TI's and Band-Inversion (BI)'s that would dramatically broaden the scope and understanding of surface electronic structure of new types of topological and band-inverted materials, providing a new paradigm for the design of conductive surfaces controlled by bulk properties.

Designing Materials to Revolutionize and Engineer our Future (DMREF)