Ionic liquid gating-tuned superconductor–insulator transition in PrBa₂Cu₃O₇/La₂CuO₄ bilayers

Recently, high-temperature superconductivity has been found at the interface between two Mott insulators, PrBa2Cu3O7 and La2CuO4. In this work, we demonstrate our tuning of this interface superconductor by ionic liquid gating. By varying gate voltage, VG, a superconductor–insulator phase transition was achieved. Hall-effect measurements suggest that the carrier density, which can be tuned continuously from 1.86 × 1014 to 3.78 × 1014 cm−2 for VG varying from −0.3 to −3 V, is the tuning parameter. A finite-size scaling analysis was used to analyze the superconductor–insulator phase transition, which gives a critical resistance of 14–17 kΩ and a critical exponent of zν ≈ 1.3–1.4. These values are comparable with those obtained in previous studies on ultrathin clean cuprate films gated by ionic liquid.