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تسجيل مستخدم جديدTransport in strongly-coupled graphene-LaAlO3/SrTiO3 hybrid systems
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We report on the transport properties of hybrid devices obtained by depositing graphene on a LaAlO3/SrTiO3 oxide junction hosting a 4 nm-deep two-dimensional electron system. At low graphene-oxide inter-layer bias the two electron systems are electrically isolated, despite their small spatial separation, and very efficient reciprocal gating is shown. A pronounced rectifying behavior is observed for larger bias values and ascribed to the interplay between electrostatic depletion and tunneling across the LaAlO3 barrier. The relevance of these results in the context of strongly-coupled bilayer systems is discussed.
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The oxide heterostructure LaAlO3/SrTiO3 supports a two-dimensional electron liquid with a variety of competing phases including magnetism, superconductivity and weak antilocalization due to Rashba spin-orbit coupling. Further confinement of this 2D e
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TiO3 (LAO/STO) heterointerface separated by a natural insulating barrier of LAO (as thin as 2 nm). Applying a drive current (Idrive) in the graphene layer induces a negative drag voltage at the LAO/STO interface in the vicinity of the superconducting transition, which is attributed to the supercurrent drag effect, arising from the interlayer interactions involving the superconducting carriers. Benefiting from the high tunability of both layers and the ultra-small interlayer spacing, an extremely large interlayer current coupling ratio (r = |Idrag/Idrive|, Idrag: the equivalent drag current at LAO/STO interface) is eventually achieved, surpassing conventional systems consisting of normal metal and superconducting films by two orders of magnitude. More strikingly, this ratio is estimated to be up to 10^5 at the zero-temperature limit. The unique temperature- and carrier density/polarity-dependent behaviors suggest a brand-new microscopic interaction mechanism accounting for the observed giant supercurrent drag effect. Our study is anticipated to inspire further exploration of hybrid interlayer coupling via utilization of newly-emerging two-dimensional electronic systems, in particular those exhibiting long-range electronic and magnetic orders.
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