Correlation between superconducting transition temperatures and carrier densities in Te- and S-substituted FeSe thin films
Fuyuki Nabeshima, Tomoya Ishikawa, Naoki Shikama, Atsutaka Maeda
Abstract
We comparatively investigated the transport properties for S- and Te-substituted FeSe thin films under magnetic fields to clarify the origin of the contrasting behavior of the superconducting transition temperature in S and Te substitution. A classical two-carrier analysis revealed that the carrier densities of the films increased with increasing Te content, while no significant change was observed for the S substitution, which suggests a correlation between ${T}_{\mathrm{c}}$ and the carrier densities. These observations suggest that the structural transition affects the electronic structure in a different manner between Fe(Se,S) and Fe(Se,Te) and that this fact is the direct cause of the difference in the ${T}_{\mathrm{c}}$ behaviors at the end point of the structural transition.