Combinatorial film and high-throughput characterization methods of phase diagram for high-<i>T</i><sub>c</sub> superconductors

<sec> Cuprate and iron-based superconductors are known as the only two types of high-<i>T</i>_c superconductors. The mechanism of high-<i>T</i>_c superconductivity is the most challenging issue in the field. Building accurate high-dimensional phase diagram and exploring key parameters that determine <i>T</i>_c, would be essential to the comprehension of high-<i>T</i>_c mechanism. The electronic phase diagrams of cuprate superconductors show complexity and diversity, for the strong coupling and interplay among lattice, orbital, charge and spin degrees of freedom. It is tough to construct a high-dimensional holographic phase diagram and obtain quantitative laws by traditional research methods. Fortunately, the high-throughput synthesis and fast screening techniques enable to probe the phase diagram via line-by-line or map scanning modes, and thereby are expected to obtain high-dimensional phase diagram and key superconducting parameters in a much efficient way.</sec><sec> In this article, electronic phase diagrams of cuprate superconductors that are obtained mainly by electrical transport measurements, are briefly summarized in the view of cation substitutions, oxygen variation in the parent compounds, electric double-layer gating (electrostatic/electrochemical manipulation) and magnetic field. We introduce the preparation methods for combinatorial film based on the developed pulsed laser deposition and oxide molecular beam epitaxy techniques, as well as corresponding scale-span high-throughput measurement techniques. These high-throughput techniques have been successfully applied in the research of interface superconductivity, quantum phase transition, and so on. The novel high-throughput superconductivity research mode will play an indispensable role in the construction of the high-dimensional holographic phase diagram, the comprehension of high-<i>T</i>_c mechanism, and practical applications of superconductors.</sec>