Research Findings Lead to a Greater Understanding of 2D Superfluids and Their Impact on Power Systems

If researchers and design engineers can achieve superconductivity at room temperature, i.e., a material with zero electrical resistance at room temperature, it could revolutionize the power electronics industry. 

According to scientists from Universität Hamburg and the Cluster of Excellence, strong evidence of superfluidity in a central model system, a two-dimensional gas cloud, has been observed for the first time. 

 

Room Temperature Superconductors

Superconductivity is vital in electronics because superconducting electronics will be able to provide devices and circuits with properties currently not seen in any other known technology. Namely, superconducting electronics will be far more reliable and efficient, wasting far less energy through heat loss. 

Researchers are so hopeful that plans are already underway to replace current power grids with superconducting power grids by 2030.

Before this is possible, however, scientists will need to find a way to achieve superconductivity at room temperature and practically apply it, which is proving to be quite challenging. 

 

An illustration of two superfluids separated by a barrier. Their wave nature allows the particles to oscillate back and forth between the two sides. Image credited to Electron Studios, UHH, Mortiz
 

The Josephson Effect

The Josephson effect is the phenomenon of a supercurrent, a current that flows indefinitely without any voltage applied to it, across a Josephson junction (JJ) device, which consists of two or more superconductors by a weak link. It was first observed in 1962, and now, for the first time, Josephson oscillations in a two-dimensional (2D) Fermi gas have been observed by researchers. 

These Fermi gases consist of a "breath of nothing," namely a gas cloud of only a few thousand atoms. If they are cooled to a few millionths of a degree above absolute zero, they become superfluid. They can now be used to study superfluids in which particles interact strongly with one another and exist only in two dimensions. This combination appears to be at the core of high-temperature superconductivity, but not much is known about it. 

"We were amazed at how the Josephson oscillations were visible in our experiment. This is clear evidence of phase coherence in our ultracold 2D Fermi gas," says first author Niclas Luick. "The high degree of control we have over our system has also allowed us to measure the critical current above which the superfluidity breaks down."

According to the researchers, their discovery could pave the way for new opportunities to gain insights into the nature of strongly correlated 2D superfluids that are difficult to simulate but are nevertheless hugely important for modern physics and, consequently, electrical engineering.