Researchers from the University of Maryland, including Matthew Toole, Nileema Sharma, James McKenzie, Fangjun Cheng, Sheng Ran, and Xiaolong Liu, have recently published a study in the journal Nature Communications that sheds light on the origins of spatially periodic modulations of the superconducting gap in certain materials. This research could have significant implications for the energy sector, particularly in the development of more efficient and robust superconducting materials for energy transmission and storage.
The study focuses on bulk FeSe, a material known for its superconducting properties. The researchers used advanced scanning tunneling microscopy techniques with superconductive tips to investigate the behavior of FeSe at the atomic level. This approach allowed them to achieve enhanced energy resolution and observe phenomena such as Josephson tunneling, which occurs when superconducting currents flow between two superconductors separated by a thin insulating barrier.
One of the key findings of the study is the identification of subsurface magnetic scatterers in FeSe, which are associated with Yu-Shiba-Rusinov states. These states are known to disrupt superconductivity locally, but the researchers observed that they also induce particle-hole symmetric gap modulations. This means that the superconducting gap, which is the energy range where superconductivity occurs, is not uniform but instead varies periodically in space.
The researchers also noted that these gap modulations are accompanied by spatial variations in the Josephson current, which is the supercurrent that flows between two superconductors. The wavevectors of these modulations are consistent with a phenomenon known as pair-breaking scattering interference (PBSI), which was proposed as an alternative mechanism to explain gap modulations without the need for finite-momentum pairing.
To further validate their findings, the researchers employed phase-referenced quasiparticle interference imaging, a technique that provides an independent and direct probe of PBSI beyond gap mapping. This approach confirmed the presence of PBSI in FeSe, establishing it as a viable origin of gap modulations in superconductors that lack preexisting charge or spin density wave orders.
The practical applications of this research for the energy sector are significant. Superconductors are materials that can conduct electricity without resistance, making them highly efficient for energy transmission and storage. However, their practical use is often limited by factors such as the need for extremely low temperatures and the presence of local disruptions in superconductivity. By understanding and controlling the mechanisms behind gap modulations, researchers can potentially develop more robust and efficient superconducting materials that operate at higher temperatures and are less susceptible to disruptions.
In conclusion, the study by Toole et al. provides valuable insights into the behavior of superconducting materials at the atomic level. Their findings could pave the way for the development of advanced superconductors that could revolutionize the energy sector by enabling more efficient and reliable energy transmission and storage systems. The research was published in the journal Nature Communications, a reputable source for cutting-edge scientific research.
This article is based on research available at arXiv.