Researchers at Harvard University led by Philip Kim have advanced superconductivity technology by using copper oxide to create high-temperature superconducting diodes. This development is crucial for quantum computing and represents an important step in manipulating and understanding exotic materials and quantum states. Credit: SciTechDaily.com
Manufacturing methods can facilitate material discovery.
- A team at Harvard University led by Philip Kim is innovating high-temperature superconductors using copper oxides.
- Developed the world’s first superconducting diode, quantum computing.
- We demonstrated directional supercurrent and quantum state control in BSCCO.
Superconductors have intrigued physicists for decades. However, although these materials allow complete, lossless electron flow, they typically exhibit this quantum mechanical property only at very low temperatures, above a few degrees. absolute temperature – Regarding making them impractical.
A research team led by Philip Kim, a professor of physics and applied physics at Harvard University, has demonstrated a new strategy for making and manipulating a widely studied class of high-temperature superconductors called cuprates, which This material has paved the way for the engineering of new and unusual forms of superconductors that were previously unattainable.
Using a unique low-temperature device manufacturing method, Kim and his team report in the journal science This is a promising candidate for the world’s first high-temperature superconducting diode (essentially a switch that allows current to flow in one direction) made of thin copper oxide crystals. Such devices could theoretically fuel emerging industries like quantum computing, which relies on temporary mechanical phenomena that are difficult to sustain.
![Twisted copper oxide superconductor](https://scitechdaily.com/images/Twisted-Cuprate-Superconductor-777x486.jpg)
Graphical representation of stacked twisted cuprate superconductors with accompanying data in the background.Credits: Lucy Yip, Yoshi Saito, Alex Cui, Frank Chao
“In fact, high-temperature superconducting diodes can be realized without applying a magnetic field, opening a new window of exploration into the study of unusual materials,” Professor Kim said.
Copper oxide is a copper oxide that turned the world of physics upside down several decades ago by showing that it becomes superconducting at much higher temperatures than theorists had thought. “Higher” is a relative term (current record for copper oxide superconductors is -225) Fahrenheit). However, handling these materials without destroying the superconducting phase is extremely complex due to their complex electronic and structural features.
The team’s experiments were led by SY Frank Zhao, a former student and current postdoctoral fellow in the Griffin School of Arts and Sciences. Massachusetts Institute of Technology. Using air-free cryogenic crystal manipulation methods in ultra-pure argon, Zhao created his two extremely thin bismuth strontium calcium copper oxides, called BSCCO (“Bisco”). We designed a clean interface between the layers. BSCCO is considered a “high temperature” superconductor because it begins superconducting at about -288 degrees Fahrenheit. This is very cold by practical standards, but surprisingly high for a superconductor, which typically needs to be cooled to about -400 degrees Celsius.
Zhao first divided the BSCCO into two layers that are 1/1000th the width of a human hair. They then stacked the two layers at -130°C with a 45-degree twist, like an ice cream sandwich with diagonal wafers, to maintain superconductivity at the fragile interface.
The research team found that the maximum supercurrent that can pass through an interface without resistance depends on the direction of the current. Importantly, the team also demonstrated electronic control of the interfacial quantum state by reversing this polarity. This control effectively enabled the creation of switchable high-temperature superconducting diodes. This is a demonstration of fundamental physics that could one day be incorporated into computing technologies such as qubits.
“This is a starting point to study topological phases characterized by quantum states protected from imperfections,” Zhao said.
Reference: “Time reversal symmetry breaking superconductivity between twisted cuprate superconductors” SY Frank Zhao, Xiaomeng Cui, Pavel A. Volkov, Hyobin Yoo, Sangmin Lee, Jules A. Gardener, Austin J. Akey, Rebecca Engelke, Yuval Ronen, Ruidan Zhong, Genda Gu, Stefan Prag, Tarun Tumul, Miyoung Kim, Marcel Franz, Jedediah H. Pixley, Nicola Poccia, Philip Kim, December 7, 2023, science.
DOI: 10.1126/science.abl8371
The Harvard team collaborated with colleagues Marcel Franz of the University of British Columbia and Jed Pixley of Rutgers University. Their team had previously performed precise theoretical calculations. predicted Behavior of copper oxide superconductors wide range The torsion angle. Matching the experimental observations also required the development of a new theory, which was done by Pavel A. Volkov at the University of Connecticut.
This research was supported in part by the National Science Foundation, Department of Defense, and Department of Energy.