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. This composition dependence of the carrier density well corresponds to the Tc behavior. The clear correlation between Tc and the carrier densities suggests 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 Tc behaviors at the end point of the structural transition.
@article{arxiv.1906.04894,
title = {Close correlation between superconducting transition temperatures and carrier densities in Te- and S-substituted FeSe thin films},
author = {Fuyuki Nabeshima and Tomoya Ishikawa and Naoki Shikama and Atsutaka Maeda},
journal= {arXiv preprint arXiv:1906.04894},
year = {2020}
}