Researchers from ShanghaiTech University and other institutions have made a significant discovery in the field of superconductivity, particularly in iron-based superconductors. Their work, published in the journal Nature Physics, sheds light on the complex interplay between charge-stripe order, superconductivity, and exotic quantum states within these materials.
The team, led by Professor Can-Li Song and Qi-Kun Xue from ShanghaiTech University, utilized spectroscopic-imaging scanning tunneling microscopy to study epitaxial films of Ba(Fe0.94Co0.06)2As2. This advanced technique allowed them to probe the electronic structure and behavior of the material at the atomic scale.
The researchers discovered an incommensurate charge-stripe order within the material, aligned with the Fe-Fe bond direction and nucleated inside magnetic vortices. These vortices are regions where superconductivity is locally suppressed in the presence of a magnetic field. The charge modulations were found to intensify at the vortex core and extend far into the surrounding area, persisting within the superconducting gap.
One of the most striking findings was the modulation of Andreev bound states—the quantum states that form within the vortices—by the charge order. This modulation led to the creation of two distinct types of vortices: abelian vortices with half-odd-integer level quantization and non-abelian vortices with integer-quantized core states that host a Majorana zero mode. Majorana zero modes are exotic quantum states that have been proposed as potential building blocks for topological quantum computers.
The distinct vortex types were distinguished by the registry of their centers relative to the charge-stripe pattern and remained robust even in ultrathin films, as thin as 2.5 unit cells. This robustness suggests that the observed phenomena are intrinsic to the material and not merely a surface effect.
The practical applications of this research for the energy sector are still in the early stages of exploration. However, the insights gained into the intertwined phenomena of charge-stripe order, pair-density-wave modulations, and Majorana physics could potentially contribute to the development of more efficient and robust superconducting materials. These materials could find applications in various energy technologies, such as lossless power transmission, compact and efficient power generation, and advanced energy storage systems.
The research was published in the journal Nature Physics, and it represents a significant step forward in our understanding of the complex behaviors that emerge in superconducting materials under magnetic fields. As the energy sector continues to seek innovative solutions for efficient and sustainable power generation and distribution, the insights from this study could play a crucial role in advancing these technologies.
Source: Nature Physics, “Intertwined Charge Stripes and Majorana Zero Modes in An Iron-Based Superconductor”
This article is based on research available at arXiv.