Giant supercurrent drag effect between graphene and LaAlO3/SrTiO3 interface

Recent advances in the manufacturing of graphene-based heterostructures have enabled the investigation of interlayer interaction phenomena in a wide parameter space and led to the discovery of intriguing interlayer correlated effects. Here, via utilizing the double-layer two-dimensional electron systems consisting of graphene and the superconducting LaAlO3/SrTiO3 heterointerface, the anomalous interlayer interaction between normal conductor and superconductor is explored via drag measurements. Negative drag signals are observed in the vicinity of the superconducting transition, and the emergence of an equivalent drag current flowing in the superconducting drag layer is verified. This effect is highly tunable by multiple external fields and exhibits giant current coupling ratio up to 50 in the zero-temperature limit, which may find its applications in designing novel superconducting electronic devices. Furthermore, the polarity and the special exponential-like temperature dependence of the current coupling ratio point to a brand-new mechanism. This study provides deep insight for future theoretical studies of interlayer coupling involving superconductors.