Two-dimensional Superconductivity at a Cu-Cu2O Interface, Anthony T. Fiory and Dale R. Harshman [arXiv]
Superconductivity in native Cu2O on Cu is considered for an interfacial double charge layer induced by adsorption of sub-monolayer 4He at temperature T ~ 4 K. Evidence for superconductivity associated with 4He adsorption is found in data for the Cu work function and the shielding of patch and lattice-strain electric fields. In the model presented for interfacial superconductivity, pairing of holes in Cu2O is mediated by Coulomb interactions with the screening elections induced in the Cu [1]. Based on a theory for layered superconductors, the intrinsic transition temperature, TC = βn1/2/ζ, is determined by sheet charge density n, transverse distance between hole and electron layers ζ, and universal constant β = 1247.4(3.7) K-Å2[1]. Using parameters derived from experiment,results for T = 4.2 K are n = 1.6 <\times>1012 cm-2, TC ≃ 7.9 K and Berezinskiĭ-Kosterlitz-Thouless temperature TBKT ≃ 4.4 K. Helium desorption causes superconductivity to vanish above T ≃ 4.8 K.
[1] D. R. Harshman and A. T. Fiory, Physica C: Supercond. Applic. 632, 1354600 (2025).
Abstract: A. T. Fiory and D. R. Harshman, APS Global Physics Summit, Denver, Colorado, 15-20 March 2026.
