2024/02/05 by Larissa B. Little, Little, Larissa B., J. R. M. COULTER +23
Materials Science · Physics and Astronomy · #Advanced Condensed Matter Physics #FOS: Physical sciences #Magnetic and transport properties of perovskites and related materials #Physics of Superconductivity and Magnetism #Superconductivity (cond-mat.supr-con)
paper · pdf · doi:10.48550/arxiv.2402.03238
openalex publication_date 2024/02/05 · openalex created_date 2024/02/07 · openalex updated_date 2026/08/01
YBa2Cu3O7-δ (YBCO) has favorable macroscopic superconducting properties of Tc up to 93 K and Hc2 up to 150 T. However, its nanoscale electronic structure remains mysterious because bulk-like electronic properties are not preserved near the surface of cleaved samples for easy access by local or surface-sensitive probes. It has been hypothesized that Ca-doping at the Y site could induce an alternate cleavage plane that mitigates this issue. We use scanning tunneling microscopy (STM) to study both Ca-free and 10% Ca-doped YBCO, and find that the Ca-doped samples do indeed cleave on an alternate plane, yielding a spatially-disordered partial (Y,Ca) layer. Our density functional theory calculations support the increased likelihood of this new cleavage plane in Ca-doped YBCO. On this surface, we image a superconducting gap with average value 24 ± 3 meV and characteristic length scale 1-2 nm, similar to Bi-based high-Tc cuprates, but the first map of gap inhomogeneity in the YBCO family.