Researchers at the Zavoisky Physical-Technical Institute and the Southern Scientific Center of RAS, in Russia, have recently fabricated quasi-2-D superconductors at the interface between a ferroelectric Ba0.8Sr0.2TiO3 film and an insulating parent compound of La2CuO4. Their study, presented in a paper published in Physical Review Letters, is the first to achieve superconductivity in a heterostructure consisting of a ferroelectric and an insulator.

The idea of forming a quasi-2-D superconducting layer at the between two different compounds has been around for several years. One past study, for instance, tried to achieve this by creating a thin superconducting layer between two insulating oxides (LaAlO3 and SrTiO3) with a critical temperature of 300mK. Other researchers observed the thin superconducting layer in bilayers of an insulator (La2CuO4) and a metal (La1.55Sr0.45CuO4), neither of which is superconducting in isolation.

"Here we put forward the idea that thin charged layer on the interface between ferroelectric and insulator is formed in order to screen the ," Viktor Kabanov and Rinat Mamin, two researchers who carried out the study, told via email. "This thin layer may be conducting or superconducting depending on the properties of the insulator. In order to get a superconducting layer, we chose La2CuO4 – an insulator that becomes a high Tc superconductor when it is doped by carriers."

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