Two-step superconductor-insulator transitions in iron chalcogenide superconductors
The superconductor-insulator transition is an archetypal example of a quantum phase transition that plays a crucial role in physics and statistical mechanics. Belonging to different universality classes, the classical and quantum percolative transitions usually manifest in different systems and are studied separately. Here, we fabricate thickness-gradient ${\mathrm{Fe}}_{y}{\mathrm{Te}}_{1\ensuremath{-}x}{\mathrm{Se}}_{x}$ (FTS) films and observe the existence of these two transitions. Variation in the film thickness, which controls substrate misfit and leads to a modification of Fe concentration, results in a superconducting quantum percolative transition. By exposing FTS films to air, we observe a shift in electrical resistivity behavior and a superconducting classical percolative transition. FTS films subjected to the two treatments exhibit very similar phase diagrams, except for different critical exponents. Remarkably, we identify a two-step superconductor-insulator transition at low temperature, where the appearance of superconductive zero resistivity coincides with a sign change in the temperature derivative of electrical resistivity in the normal state. Our analysis can provide a universal scheme to categorize the superconductor-insulator transition in various copper-oxide and iron-based superconductors.
Authors
- Mingyang Qin (ORCID: https://orcid.org/0000-0001-5341-7465)
- Wenxin Cheng
- Jie Yuan (ORCID: https://orcid.org/0000-0002-0126-4927)
- Haiwen Liu (ORCID: https://orcid.org/0000-0002-0007-3117)
- Yangmu Li (ORCID: https://orcid.org/0000-0003-0886-2919)
- Zefeng Lin (ORCID: https://orcid.org/0000-0002-5407-9696)
- Kui Jin
- Ruozhou Zhang
- Xingyu Jiang (ORCID: https://orcid.org/0009-0003-4109-8542)
- Liping Zhang (ORCID: https://orcid.org/0000-0002-9754-5829)
- Xuewei Wang (ORCID: https://orcid.org/0000-0003-3679-7421)
- Xu Li
- Qihong Chen (ORCID: https://orcid.org/0000-0002-6039-0456)
- Juan Xu (ORCID: https://orcid.org/0000-0003-3472-2055)
- Xiangyu Zhang (ORCID: https://orcid.org/0009-0003-0940-5565)
- Peiyu Xiong
Institutions
- Chinese Academy of Sciences (CN)
- Beijing Normal University (CN)
- Southern University of Science and Technology (CN)
- Wuhan University (CN)
- Songshan Lake Materials Laboratory (CN)
- FZU ‒ Institute of Physics of the Academy of Sciences of the Czech Republic (CZ)
- Beijing Academy of Quantum Information Sciences (CN)
- University of Chinese Academy of Sciences (CN)
Publication Details
- Journal
- Physical review. B./Physical review. B
- Published
- 2025-02-26
- DOI
- https://doi.org/10.1103/physrevb.111.l060506
- Primary Topic
- Iron-based superconductors research
- Type
- article
- Field-Weighted Citation Impact
- 0.00
Funders
- Kent State University
- National Natural Science Foundation of China
- Chinese Academy of Sciences
- Beijing Municipal Natural Science Foundation
- National Key Research and Development Program of China
- Fundamental Research Funds for the Central Universities