Competing Constraints on Superconductivity in Thick FeSe films

Fuente: arXiv
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Main Authors: He, Ya-Xun, Liu, Xing-Jian, Wang, Qun, Chen, Ting, Ali, Hassan, Zhang, Jia-Ying, Kang, Bao-Juan, Zhang, Zheng, Ge, Jun-Yi
Format: Preprint
Published: 2026
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author He, Ya-Xun
Liu, Xing-Jian
Wang, Qun
Chen, Ting
Ali, Hassan
Zhang, Jia-Ying
Kang, Bao-Juan
Zhang, Zheng
Ge, Jun-Yi
author_facet He, Ya-Xun
Liu, Xing-Jian
Wang, Qun
Chen, Ting
Ali, Hassan
Zhang, Jia-Ying
Kang, Bao-Juan
Zhang, Zheng
Ge, Jun-Yi
contents Superconducting films emerge from the complex interplay of multiple growth parameters, making their optimization challenging. In iron-based superconductors, compressive strain is known to enhance the transition temperature (Tc) of FeSe films, yet reported Tc values vary widely even on identical substrates, indicating factors beyond strain are critical. Here, we develop a high-throughput off-center pulsed laser deposition strategy that transforms plume inhomogeneity into combinatorial FeSe film libraries with continuous gradients in lattice parameter, composition, and disorder. We discover that the maximum Tc does not coincide with the plume center but can shift off-center, revealing a competition between favorable c-axis expansion, stoichiometry, and defect scattering. Systematic characterization of 80 thick films (>50 nm), combined with interpretable machine learning, shows that besides the strong correlate of c-axis lattice parameter to Tc, the stoichiometry and disorder scattering impose critical constraints on the achievable transition temperature, defining a narrow optimization window rather than a simple monotonic relationship. This framework yields Tconset=17.1 K in thick FeSe films and establishes a general framework combining combinatorial synthesis with machine learning to uncover constrained optimization landscapes in complex functional materials.
format Preprint
id arxiv_https___arxiv_org_abs_2604_19443
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Competing Constraints on Superconductivity in Thick FeSe films
He, Ya-Xun
Liu, Xing-Jian
Wang, Qun
Chen, Ting
Ali, Hassan
Zhang, Jia-Ying
Kang, Bao-Juan
Zhang, Zheng
Ge, Jun-Yi
Superconductivity
Materials Science
Superconducting films emerge from the complex interplay of multiple growth parameters, making their optimization challenging. In iron-based superconductors, compressive strain is known to enhance the transition temperature (Tc) of FeSe films, yet reported Tc values vary widely even on identical substrates, indicating factors beyond strain are critical. Here, we develop a high-throughput off-center pulsed laser deposition strategy that transforms plume inhomogeneity into combinatorial FeSe film libraries with continuous gradients in lattice parameter, composition, and disorder. We discover that the maximum Tc does not coincide with the plume center but can shift off-center, revealing a competition between favorable c-axis expansion, stoichiometry, and defect scattering. Systematic characterization of 80 thick films (>50 nm), combined with interpretable machine learning, shows that besides the strong correlate of c-axis lattice parameter to Tc, the stoichiometry and disorder scattering impose critical constraints on the achievable transition temperature, defining a narrow optimization window rather than a simple monotonic relationship. This framework yields Tconset=17.1 K in thick FeSe films and establishes a general framework combining combinatorial synthesis with machine learning to uncover constrained optimization landscapes in complex functional materials.
title Competing Constraints on Superconductivity in Thick FeSe films
topic Superconductivity
Materials Science
url https://arxiv.org/abs/2604.19443