The influence of the in-plane lattice constant on the superconducting transition temperature of FeSe0.7Te0.3 thin films

作者：Yuan, Feifei; Iida, Kazumasa^*; Grinenko, Vadim; Chekhonin, Paul; Pukenas, Aurimas; Skrotzki, Werner; Sakoda, Masahito; Naito, Michio; Sala, Alberto; Putti, Marina; Yamashita, Aichi; Takano, Yoshihiko; Shi, Zhixiang^*; Nielsch, Kornelius; Huehne, Ruben

来源：AIP Advances, 2017, 7(6): 065015.

DOI：10.1063/1.4989566

Epitaxial Fe(Se, Te) thin films were prepared by pulsed laser deposition on (La0.18Sr0.82)(Al0.59Ta0.41) O-3 (LSAT), CaF2-buffered LSAT and bare CaF2 substrates, which exhibit an almost identical in-plane lattice parameter. The composition of all Fe(Se, Te) films were determined to be FeSe0.7Te0.3 by energy dispersive X-ray spectroscopy, irrespective of the substrate. Albeit the lattice parameters of all templates have comparable values, the in-plane lattice parameter of the FeSe0.7Te0.3 films varies significantly. We found that the superconducting transition temperature (T-c) of FeSe0.7Te0.3 thin films is strongly correlated with their a-axis lattice parameter. The highest Tc of over 19 K was observed for the film on bare CaF2 substrate, which is related to unexpectedly large in-plane compressive strain originating mostly from the thermal expansion mismatch between the FeSe0.7Te0.3 film and the substrate.

• 出版日期2017-6
• 单位东南大学