标题： 在过掺杂CuBa2Ca3Cu4O10+d中控制118 K多能隙超导性的晶格量子几何 显示英文标题

标题： Lattice Quantum Geometry Controlling 118 K Multigap Superconductivity in Heavily Overdoped CuBa2Ca3Cu4O10+d

摘要： 同步加速器X射线衍射已被用于研究CuBa2Ca3Cu4O10+d (Cu1234)的热结构演化，这是一种具有高临界温度(Tc 118 K)、高临界电流密度和大上临界磁场的超导体。这种铜氧化物在纳米尺度的晶格几何结构属于原子极限下的天然异质结构类，类似于由莫特绝缘体单元中界面空间电荷形成的人工高Tc超晶格，这些超晶格被金属单元插入。温度依赖的晶格参数显示在TC处出现明显的结构转变，表现为TC以下c轴的下降和面内Cu-O的负热膨胀。这些结果提供了与由于多个超导能隙开启引起的化学势变化相关的晶格重组的明确证据。此外，在200 K以上的温度下观察到了氧缺陷重新排列的证据。我们构建了一个相图，将温度、c/a轴比和面内Cu-O应变相关联，确定了与能隙开启和氧重新排列相关的区域。这些发现为晶格几何如何控制超导性提供了新的见解，以指导先进纳米尺度超导人工量子异质结构的材料设计。 显示英文摘要

摘要： Synchrotron X-ray diffraction has been used to study the thermal structure evolution in CuBa2Ca3Cu4O10+d (Cu1234), a superconductor which exhibits a high critical temperature (Tc 118 K), high critical current density and large upper critical magnetic field. The lattice geometry at nanoscale of this cuprate belongs to the class of natural heterostructures at atomic limit like the artificial high Tc superlattices made of interface space charge in Mott insulator units intercalated by metal units. Temperature-dependent lattice parameters reveal a distinct structural transition at TC characterized by a drop of the c-axis and in plane Cu-O negative thermal expansion below TC. These results provide clear evidence of lattice reorganization associated with the chemical potential changes due to the opening of multiple superconducting gaps. Additionally, evidence for oxygen defects rearrangement is observed at temperatures above 200 K. We construct a phase diagram correlating temperature, the c/a axis ratio, and in plane Cu-O strain, identifying regions associated with gaps opening and oxygen rearrangement. These findings provide new insights into how lattice geometry control superconductivity to inform the material design of advanced nanoscale superconducting artificial quantum heterostructures.