1] IFW Dresden, P.O. Box 270116, 01171 Dresden, Germany [2] Dresden University of Technology, 01062 Dresden, Germany.
Nat Commun. 2013;4:2877. doi: 10.1038/ncomms3877.
The discovery of superconductivity with a transition temperature, Tc, up to 65 K in single-layer FeSe (bulk Tc=8 K) films grown on SrTiO3 substrates has attracted special attention to Fe-based thin films. The high Tc is a consequence of the combined effect of electron transfer from the oxygen-vacant substrate to the FeSe thin film and lattice tensile strain. Here we demonstrate the realization of superconductivity in the parent compound BaFe2As2 (no bulk Tc) just by tensile lattice strain without charge doping. We investigate the interplay between strain and superconductivity in epitaxial BaFe2As2 thin films on Fe-buffered MgAl2O4 single crystalline substrates. The strong interfacial bonding between Fe and the FeAs sublattice increases the Fe-Fe distance due to the lattice misfit, which leads to a suppression of the antiferromagnetic spin density wave and induces superconductivity with bulk Tc≈10 K. These results highlight the role of structural changes in controlling the phase diagram of Fe-based superconductors.
在 SrTiO3 衬底上生长的单层 FeSe（体 Tc=8 K）薄膜中，发现超导转变温度 Tc 高达 65 K，这引起了人们对 Fe 基薄膜的特别关注。高 Tc 是氧空位衬底向 FeSe 薄膜电子转移和晶格拉伸应变综合作用的结果。在这里，我们证明了通过没有电荷掺杂的晶格拉伸应变，在母体化合物 BaFe2As2（没有体 Tc）中实现了超导。我们研究了外延 BaFe2As2 薄膜在 Fe 缓冲 MgAl2O4 单晶衬底上的应变和超导之间的相互作用。Fe 与 FeAs 亚晶格之间的强界面键合由于晶格失配而增加了 Fe-Fe 距离，从而抑制了反铁磁自旋密度波并诱导具有体 Tc≈10 K 的超导。这些结果强调了结构变化在控制 Fe 基超导体相图中的作用。
