Annealing, acid, and alcoholic beverage effects on Fe1+yTe0.6Se0.4

TL;DR

This study compares various annealing and immersion methods to induce superconductivity in Fe1+yTe0.6Se0.4, finding that oxidation techniques effectively trigger superconductivity by removing excess iron, with bulk or surface effects depending on the method.

Contribution

It systematically evaluates different annealing and immersion treatments, revealing how oxidation induces superconductivity in Fe1+yTe0.6Se0.4, and proposes a mechanism for this process.

Findings

Oxygen annealing induces bulk superconductivity.

Iodine, acid, and alcoholic beverages induce surface superconductivity.

Vacuum and N2 annealing are ineffective.

Abstract

We have systematically investigated and compared different methods to induce superconductivity in iron chalcogenide Fe1+yTe0.6Se0.4 including annealing in vacuum, N2, O2, I2 atmosphere, and immersing samples into acid and alcoholic beverages. Vacuum and N2 annealing are proved to be ineffective to induce superconductivity in Fe1+yTe0.6Se0.4 single crystal. O2 and I2 annealing, acid and alcoholic beverages can induce superconductivity by oxidizing the excess Fe in the sample. Superconductivity in O2 annealed sample is in bulk nature, while I2, acid and alcoholic beverages can only induce superconductivity near the surface. By comparing different effects of O2, I2, acid and alcoholic beverages, we propose a scenario to explain how the superconductivity is induced in the non-superconducting as-grown Fe1+yTe0.6Se0.4.