Observation of selective surface element substitution in FeTe<sub>0.5</sub>Se<sub>0.5</sub> superconductor thin film exposed to ambient air by synchrotron radiation spectroscopy

Observation of selective surface element substitution in FeTe_0.5Se_0.5 superconductor thin film exposed to ambient air by synchrotron radiation spectroscopy

Zhang Nian^{1, 2}, Liu Chen¹, Zhao Jia-Li¹, Lei Tao¹, Wang Jia-Ou¹, Qian Hai-Jie¹, Wu Rui¹, Yan Lei³, Guo Hai-Zhong³, Ibrahim Kurash^{1, †,}

A schematic representation of experimental processes. (a) A 100 nm superconductive thin film was deposited by the PLD method on an Nb-doped STO substrate. (b) The film was exposed to ambient air at room temperature in a super-clean laboratory for one month. (c) The air-contacted film was re-introduced into the ultrahigh vacuum chamber and was subjected to cycles of annealing and etching treatments, which was followed by subsequential electronic structure measurements.