Researchers from the KTH Royal Institute of Technology in Stockholm, Stanford University, TD Lee Institute in Shanghai, and AIST in Tsukuba have made an intriguing discovery regarding superconductors. In a study published in the journal Science, they report the existence of a new type of superconducting vortex, challenging the prevailing understanding of electronic flow in superconductors.
Superconductors can exhibit quantum vortices, which are electron tornadoes with significant implications for applications such as quantum sensors. These vortices are formed when an external magnetic field is applied to a superconductor, causing quantized magnetic flux tubes to penetrate and create vortices.
Previously, it was believed that each quantum vortex carried a single quantum of magnetic flux as they passed through superconductors. However, the international research team found that the magnetic flux produced by vortices can actually be divided into a wider range of values than previously thought. This finding not only deepens our understanding of superconductivity fundamentals but also holds potential for applications in superconducting electronics.
Using the Superconducting Quantum Interference Device (SQUID) at Stanford University, the team demonstrated the existence of quantum vortices in a single electronic band. Research scientist Yusuke Iguchi and Professor Kathryn A. Moler were able to create and manipulate these fractional quantum vortices at a microscopic level.
This discovery confirms a prediction made by Professor Egor Babaev, published two decades ago, that specific types of crystals could exhibit quantum vortices where different parts of the electron population in a superconducting material form clockwise and counterclockwise vortices simultaneously. Babaev suggests that these combined quantum vortices can carry arbitrary fractions of flux quantum.
The research team conducted the experiment multiple times to ensure the accuracy of their findings, as the initial observation of this phenomenon was extremely rare. The robustness and controllability of quantum vortices suggest that they could potentially serve as information carriers in superconducting computers, opening up possibilities for advancements in quantum computation.
The study represents a significant revision of our understanding of quantum vortices in superconductors, according to Babaev and Moler. The insights gained from this research, along with the innovative methods employed by Iguchi and Moler, may have long-term implications for quantum computation platforms.