We have used atomic layer-by-layer oxide molecular beam epitaxy to grow epitaxial thin films of La2−xCaxCuO4 with x up to 0.5, greatly exceeding the solubility limit of Ca in bulk systems (x∼0.12). A comparison of the optical conductivity measured by spectroscopic ellipsometry to prior predictions from dynamical mean-field theory demonstrates that the hole concentration p is approximately equal to x. We find superconductivity with Tc of 15 to 20 K up to the highest doping levels and attribute the unusual stability of superconductivity in La2−xCaxCuO4 to the nearly identical radii of La and Ca ions, which minimizes the impact of structural disorder. We conclude that careful disorder management can greatly extend the “superconducting dome” in the phase diagram of the cuprates.

我们已经使用原子逐层氧化物分子束外延生长外延薄膜 升一种2-XC一种XC你哦4 x高达0.5，大大超过了Ca在本体体系中的溶解度极限（X～0.12）。通过光谱椭偏法测量的光导率与动态平均场理论的先前预测的比较表明空穴浓度 p 大约等于 x。我们发现超导性吨C 15 至 20 K 直至最高掺杂水平，并归因于超导性的异常稳定性 升一种2-XC一种XC你哦4La 和 Ca 离子的半径几乎相同，从而最大限度地减少了结构无序的影响。我们得出结论，仔细的无序管理可以大大扩展铜酸盐相图中的“超导圆顶”。