Tartaric acid in red wine as one of the key factors to induce superconductivity in FeTe0.8S0.2

The red wine dependence of superconductivity in FeTe0.8S0.2 was investigated. Samples with a higher shielding volume fraction had a tendency to show a higher concentration of tartaric acid in red wine. We found the tartaric acid is one of the key factors to induce superconductivity in FeTe0.8S0.2.