Enhancing superconductivity of ultrathin YBa2Cu3O7-δ films by capping non-superconducting oxides

In this study, we have explored the ways to fabricate and optimize high-quality ultrathin YBa2 Cu3 O7-δ(YBCO) films grown on single-crystal(001) SrTiO3 substrates. Nearly atomic-flat YBCO films are obtained by pulsed laser deposition.Our result shows that the termination of SrTiO3 has only a negligible effect on the properties of YBCO. In contrast, we found that capping a non-superconducting oxide layer can generally enhance the superconductivity of YBCO. PrBa2 Cu3 O7,La2 CuO4, LaMnO3, SrTiO3, and LaAlO3 have been examined as capping layers, and the minimum thickness of superconducting YBCO with capping is ~ 2 unit cells–3 unit cells. This result might be useful in constructing good-performance YBCO-based field effect devices.

脉冲激光沉积法制备双层结构铜氧化物界面高温超导（英文）

在2008年发表的一篇经典工作中, Gozar等人报道了由绝缘性的La2CuO4和金属性的La1.55Sr0.45CuO4双层薄膜构成的体系存在界面超导.一个重要的有待回答的问题是该界面超导是否强健以及具有普遍性.在Gozar等人的工作中,铜氧化物双层结构是利用特制的氧化物分子束外延设备生长的,最大Sr掺杂量仅为0.47.在本工作中,我们首次利用脉冲激光沉积法制备了铜氧化物双层结构,并重复出了上述界面超导工作.在此基础上,我们将Sr的掺杂范围大幅扩展到1. 7 0,结果表明在由La2CuO4和过掺杂的La2-xSrxCuO4构成的双层结构中界面超导非常强健和普遍.值得一提的是,我们发现在x>0.8范围内存在一个新的界面超导区间.