High-temperature interface superconductivity in bilayer copper oxide films by pulsed laser deposition  

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）

作　　者：Jia-hao Deng Tian-shuang Ren Le-le Ju Hong-rui Zhang Ji-rong Sun Bao-gen Shen Yan-wu Xie 邓佳豪;任天爽;居乐乐;张洪瑞;孙继荣;沈保根;谢燕武(Interdisciplinary Center of Quantum Information,Zhejiang Province Key Laboratory of Quantum Technology and Device,and Department of Physics,Zhejiang University,Hangzhou 310027,China;Beijing National Laboratory for Condensed Matter Physics&Institute of Physics,Chinese Academy of Sciences,Beijing 100190,China;Collaborative Innovation Center of Advanced Microstructures,Nanjing University,Nanjing 210093,China)

机构地区：[1]Interdisciplinary Center of Quantum Information,Zhejiang Province Key Laboratory of Quantum Technology and Device,and Department of Physics,Zhejiang University,Hangzhou 310027,China [2]Beijing National Laboratory for Condensed Matter Physics&Institute of Physics,Chinese Academy of Sciences,Beijing 100190,China [3]Collaborative Innovation Center of Advanced Microstructures,Nanjing University,Nanjing 210093,China

出　　处：《Science China Materials》2020年第1期128-135,共8页中国科学（材料科学（英文版）

基　　金：supported by the National Key Research and Development Program of Ministry of Science and Technology of China (2017YFA0303002, 2016YFA0300204, and 2016YFA0300701);the Fundamental Research Funds for the Central Universities

摘　　要：In a seminal work, Gozar et al. reported on the high-temperature interface superconductivity in bilayers of insulating La2Cu O4 and metallic La2-xSrxCuO4(x=0.45). An interesting question to address is how general and robust this interface superconductivity is. In the past, the cuprate bilayers were grown in a unique atomic-layer molecular beam epitaxy system, with a Sr doping range of x≤0.47, and the atomically flat interface was thought to be indispensable. Here, we have fabricated bilayers of La2CuO4 and La2-xSrxCuO4 by pulsed laser deposition. We have tried to extend the nominal doping range of Sr from the previous maximum of 0.47 to the present1.70(the nominal Sr content in the targets). X-ray diffraction result indicates that our La2-xSrxCuO4 films with x≤0.60 have very high crystalline quality;but the film crystalline structure degrades gradually with further increasing x, and finally the structure is fully lost when x reaches 1.40 and higher. Although the film quality scatters dramatically, our experiments show that there exists superconductivity for bilayers in nearly the entire over-doped Sr range, except for a non-superconducting region at x^0.80. These observations demonstrate that the interface superconductivity in copper oxides is very general and robust.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.

关 键 词：CUPRATE SUPERCONDUCTIVITY interface pulsed laser deposition high temperature superconductivity 

分 类 号：TQ131.21[化学工程—无机化工] TB383.2[一般工业技术—材料科学与工程]