Superconductor Theory Confirmed: Wave Patterns in Kagome

A recent breakthrough by a team from Würzburg University, led by Professor Ronny Thomale, has confirmed a new theory about superconductivity in Kagome metals. Published in Physical Review B, the study reveals that Cooper pairs in these metals exhibit a wave-like distribution, which opens up new possibilities for technological innovations such as superconducting diodes.

For around 15 years, researchers have been intrigued by Kagome materials, named for their star-shaped structure reminiscent of traditional Japanese basketry. Although scientists began synthesizing these metallic compounds in the lab only in 2018, their unique crystal geometry offers exciting prospects for quantum technologies.

Professor Thomale, from the Würzburg-Dresden Cluster of Excellence ct.qmat, has significantly contributed to this field with his theoretical predictions. The recent study shows that early assumptions of uniformly distributed Cooper pairs in Kagome metals were incorrect. Instead, the Cooper pairs are arranged in a wave-like pattern within the material's atomic sublattices.

In a preprint paper published on February 16, 2023, and later in Nature, Thomale's team proposed that this unique superconductivity involves Cooper pairs distributing in waves. Their recent findings directly validate this theory, showing that at ultra-low temperatures, around –272°C, electrons form Cooper pairs that move through the material without resistance, creating a quantum fluid.

Hendrik Hohmann and Matteo Dürrnagel, doctoral students involved in the research, explain that this wave-like behavior in Kagome metals resembles the condensation of steam into liquid, but occurs in the electron and Cooper pair distributions at extremely low temperatures.

The research also discovered sublattice-modulated superconductivity, where Cooper pairs are not uniformly distributed but follow a wave-like pattern. This phenomenon is due to wave-like electron distributions even before reaching superconductivity.

The experimental breakthrough was achieved by Jia-Xin Yin at the Southern University of Science and Technology in Shenzhen, China. Utilizing a scanning tunneling microscope with a superconducting tip based on the Josephson effect, the team was able to directly observe the wave-like distribution of Cooper pairs.

Professor Thomale highlights that these findings are crucial for the development of energy-efficient quantum devices. While current observations are at the atomic scale, the goal is to achieve Kagome superconductivity on a larger scale, potentially leading to new superconducting components and loss-free circuits.

In summary, the study of Kagome superconductors not only challenges previous understandings of superconductivity but also promises exciting advancements in superconducting electronics and quantum technologies.