Ybacuo Single Crystals Exhibit Decreased Superconducting Temperature with Electron Irradiation up to E/cm

The behaviour of high-temperature superconductors under intense radiation remains a key question in materials science, and recent work by A. L. Solovjov, K. Rogacki, and N. V. Shytov, alongside E. V. Petrenko, L. V. Bludova, and A. Chroneos, sheds new light on this phenomenon. The team investigates how strong electron irradiation alters the electrical properties of YBa₂Cu₃O₇₋δ single crystals, revealing a complex interplay between radiation dose, conductivity fluctuations, and the emergence of a pseudogap. Their findings demonstrate that irradiation initially suppresses superconductivity in a manner consistent with established theories, but at higher doses, fluctuations become dominant, leading to a surprising shift in the material’s behaviour. Crucially, the research identifies a specific radiation level where the material’s properties revert to those of pristine YBa₂Cu₃O₇₋δ, offering valuable insights into the resilience and potential applications of these advanced materials.

Pseudogap Origin and YBCO Superconductivity

This body of work centres on understanding the complex phenomenon of the pseudogap and its relationship to superconductivity in YBarium Copper Oxide. Researchers investigate the pseudogap, its origin, temperature dependence, and connection to superconductivity, exploring whether it is a precursor to superconductivity, a competing order, or something entirely different. YBarium Copper Oxide serves as a primary model system due to its relatively high superconducting temperature and well-characterized properties. The research also examines the impact of defects and irradiation on the pseudogap and superconducting properties, suggesting how disorder influences the electronic structure and pairing mechanisms. Applying hydrostatic pressure allows scientists to tune the electronic structure and investigate the underlying physics, while consideration of anisotropic properties reveals how the electronic structure varies between layers.

Irradiation Induces Superconductor to Insulator Transition

Scientists investigated how high-energy electron irradiation affects the properties of untwinned YBarium Copper Oxide crystals, meticulously measuring resistivity, fluctuation conductivity, and the pseudogap. Results demonstrate a linear increase in resistivity and a corresponding decrease in the superconducting temperature as the irradiation dose increased. Specifically, the critical temperature rapidly decreased, reaching zero at doses exceeding 10 × 10¹⁹ e/cm², while resistivity values increased significantly. The team observed a clear transition from a metallic to an insulating state above an irradiation dose of approximately 6.

9 × 10¹⁹ e/cm², marked by the disappearance of the pseudogap and a deviation from linear resistivity behaviour. Matthiessen’s rule, which describes how different contributions to resistivity add together, holds true for these crystals, with residual resistivity increasing substantially with irradiation. This detailed characterization of the material’s evolution provides a detailed understanding of how defects influence superconductivity.

Disorder, Fluctuations, and Superconducting Transition

This research investigated how high-energy electron irradiation affects the superconducting properties of untwinned YBarium Copper Oxide crystals, revealing a complex interplay between disorder and superconductivity. Scientists demonstrated that increasing irradiation dose linearly reduces resistivity and lowers the superconducting temperature, initially following predictions based on the Abrikosov-Gorkov theory of pair-breaking. However, at higher doses, the behaviour shifted, aligning instead with the Emery-Kivelson model which emphasizes the importance of fluctuating Cooper pairs. This transition coincided with changes in the spacing between copper-oxygen planes, the coherence length, and the region dominated by fluctuations, indicating a shift in the dominant mechanism governing superconductivity. The team observed that at a specific irradiation level, the material’s properties reverted to those of well-structured YBarium Copper Oxide, suggesting a degree of self-healing or restoration of order. Further investigation is needed to fully understand the behaviour of fluctuating Cooper pairs and the pseudogap under these conditions.