Nanowerk July 19, 2023
Spatial disorder has been shown to drive two-dimensional (2D) superconductors to an insulating phase through a superconductor–insulator transition (SIT). Numerical calculations predict that with increasing disorder, emergent electronic granularity is expected in these materials—a phenomenon where superconducting (SC) domains on the scale of the material’s coherence length are embedded in an insulating matrix and coherently coupled by Josephson tunneling. An international team of researchers (USA – SLAC National Accelerator Laboratory, Colombia) has
shown spatially resolved scanning tunneling spectroscopy (STS) measurements of the three-dimensional (3D) superconductor BaPb1−xBixO3 (BPBO), which surprisingly demonstrated three key signatures of emergent electronic granularity, having only been previously conjectured and observed in 2D thin-film systems. These signatures included the observation of emergent SC domains on the scale of the coherence length, finite energy gap over all space, and strong enhancement of spatial anticorrelation between pairing amplitude and gap magnitude as the SIT is approached. According to the researchers their observations are suggestive of 2D SC behavior embedded within a conventional 3D s-wave host, an intriguing but still unexplained interdimensional phenomenon are consistent only with dimensionality d = 2… read more… Open Access TECHNICAL ARTICLEÂ
BPBO structure and electronic phase diagram… Credit: PNAS, April 12, 2021, 118 (16) e2017810118