Quenching dependence on superconductivity in the synthesizing process of single crystals of RbxFe2-ySe2

Superconducting single crystals of Rb-intercalated FeSe compounds RbxFe2-ySe2 were prepared by using a starting material of Rb2Se as a Rb source. The superconducting properties and the surface microstructures were systematically controlled by varying the cooling rate in the quenching process. The higher cooling rate in the sample provided a higher superconducting transition temperature with highly connected superconducting mesh-like surface structure. Extremely slow-cooling process led to the complete isolation between the superconducting domains.