Defects, Electrons, and a Long-Standing Controversy

Defects, Electrons, and a Long-Standing Controversy image
September 11, 2016 | Source: Physical Review X Journal, US Department of Energy

Faster, more energy-efficient electronics could be created with topological insulators, which carry an electrical charge on just the surface, while the interior acts as an insulator. Scientists are delving into how the material's structure and chemistry correlate with its unusual electronic properties. By carefully controlling and monitoring chemical changes in the topological insulator bulk samarium hexaboride (SmB6), scientists reconciled a long-standing controversy on the diverse results on its low-temperature electrical properties and established a systematic relationship between the bulk chemistry and surface topological properties. Using chemical structures and electrical properties measured under extremely cold conditions, the team showed that electron dopants enhance the topological behavior of SmB 6 while aluminum defects and samarium vacancies suppress it.

Understanding of the mechanism paves a way to control the properties of topological insulators, as they hold great promise for next-generation energy-efficient electronics and a platform for scalable quantum computers, if their exotic surface electronic states can be selectively harnessed.
 

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