The films of FeSe on substrates have attracted attention because of their unusually high-temperature (Tc) superconducting properties whose origins continue to be debated. To disentangle the competing effects of the substrate and interlayer and intralayer processes, we present here results of density functional theory (DFT)-based analysis of the electronic structure of unsupported FeSe films consisting of 1 to 5 layers (1L-5L). Furthermore, by solving the Bardeen-Schrieffer-Cooper (BCS) equation with spin-wave exchange attraction derived from the Hubbard model, we find the superconducting critical temperature Tc for 1L-5L and bulk FeSe systems in reasonable agreement with experimental data. Our results point to the importance of correlation effects in superconducting properties of single- and multi-layer FeSe films, independently of the role of substrate.
@article{arxiv.2302.09627,
title = {Thickness dependence of superconductivity in FeSe films},
author = {Jia Shi and Duy Le and Volodymyr Turkowski and Naseem Ud Din and Tao Jiang and Qiang Gu and Talat S. Rahman},
journal= {arXiv preprint arXiv:2302.09627},
year = {2023}
}