Superconductivity in spin-orbit coupled BaBi3 formed by in situ reduction of bismuthate films

Abstract

Oxygen scavenging at oxide heterointerfaces has emerged as a powerful route for stabilizing metastable phases that exhibit interesting phenomena, including high-mobility, two-dimensional electron gases and high-Tc superconductivity. We investigate structural and chemical interactions at the heterointerface formed between Al or Eu and the charged-ordered insulator, BaBiO3, leading to emergent superconductivity at 6 K. A combination of x-ray diffraction and electron microscopy measurements shows that oxygen scavenging by the Eu and Al adlayers leads to the formation of superconducting intermetallic BaBi3 in nominal Eu/BaBiO3 and Al/BaBiO3 bilayers. Anisotropic magnetotransport measurements and current-voltage signatures of quasi-two-dimensional superconductivity are observed. The mechanisms behind quasi-two-dimensional superconductivity and the role of disorder remain to be clarified. These findings highlight the potential for the use of in situ reduction of bismuthate heterostructures as a platform for stabilizing materials with exotic functional properties. Additionally, the strong spin-orbit coupling at the Bi sites may pave the way for the realization of high-Tc topological superconductivity.

Source-reported materials — not catalogue approval

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