Superconductivity in Ion-implanted FeTe Thin films 

Iron telluride (FeTe), an intrinsically non-superconducting member of the iron chalcogenide family, can become superconducting after doping with elements such as S or Se, or through structural modifications. Many aspects of this superconducting system are still poorly understood. In order to understand the role of defects and disorder in this material, we investigated the effect of sulfur ion implantation on epitaxially grown FeTe thin films. The pristine FeTe sample exhibits an antiferromagnetic (AFM) transition around 70 K, with no indication of superconductivity. After implantation with sulfur ions, the AFM transition remains, and low temperature resistivity measurements indicate enhanced scattering from lattice defects, which is also verified by x-ray diffraction. Although no superconductivity was observed for the implanted samples, annealing can allow or inhibit superconductivity depending on the conditions. These results suggest that defects are potentially an important factor in the superconductivity of iron chalcogenides, and ion implantation provides a pathway to enable and study superconductivity in FeTe.