In a novel experiment, physicists have observed long-range quantum coherence effects due to Aharonov-Bohm interference in a topological insulator-based device. This finding opens up a new realm of possibilities for the future development of topological quantum physics and engineering. This finding could also affect the development of spin-based electronics, which may potentially replace some current electronic systems for higher energy efficiency and may provide new platforms to explore quantum information science.
The research, published in Nature Physics, is the culmination of more than 15 years of work at Princeton. It came about when Princeton scientists developed a quantum device — called a bismuth bromide (α-Bi4Br4) topological insulator — only a few nanometers thick and used it to investigate quantum coherence.
Scientists have used topological insulators to demonstrate novel quantum effects for more than a decade. The Princeton team developed their bismuth-based insulator in a previous experiment where they demonstrated its effectiveness at room temperature. But this new experiment is the first time these effects have been observed with a very long-range quantum coherence and at a relatively high temperature. Inducing and observing coherent quantum states typically requires temperatures near absolute zero on artificially designed semiconducting materials only in the presence of strong magnetic fields.
“Our experiments provide compelling evidence for the existence of long-range quantum coherence in topological hinge modes, thus opening new avenues towards the development of topological circuitry as well as using this topological method to explore and advance fundamental physics,” said M. Zahid Hasan, the Eugene Higgins Professor of Physics at Princeton University, who led the research. “Unlike conventional electronic devices, topological circuits are robust against defects and impurities, making them far less prone to energy dissipation, which is advantageous for greener applications.”
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