Unusually stronger quantum fluctuation with larger spins: Novel phenomena revealed by emergent magnetism in pressurized high-temperature superconductor FeSe

ORAL

Abstract

A counter-intuitive enhancement of quantum fluctuation with larger spins, together with a few novel physical phenomena, is discovered in studying the recently observed emergent magnetism in high-temperature superconductor FeSe under pressure. Starting with experimental crystalline structure from our high-pressure X-ray refinement, we analyze theoretically the stability of the magnetically ordered state with a realistic spin-fermion model. We find surprisingly that in comparison with the magnetically ordered Fe-pnictides, the larger spins in FeSe suffer even stronger long-range quantum fluctuation that diminishes their ordering at ambient pressure. This "fail-to-order" state then develops into an ordered state above 1GPa due to weakened fluctuation accompanying the reduction of anion height and carrier density. We further clarify the controversial nature of magnetism and its interplay with nematicity in FeSe in the same unified picture for all Fe-based superconductors. Our study establishes a generic exceptional paradigm of stronger quantum fluctuation with larger spins that complements the standard knowledge of insulating magnetism.

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Presenters

  • Wei Ku

    Tsung-Dao Lee Institute, Tsung-Dao Lee Institute & School of Physics and Astronomy, Shanghai Jiao Tong University, School of Physics and Astronomy, Shanghai JiaoTong University, Shanghai Jiao Tong University

Authors

  • Wei Ku

    Tsung-Dao Lee Institute, Tsung-Dao Lee Institute & School of Physics and Astronomy, Shanghai Jiao Tong University, School of Physics and Astronomy, Shanghai JiaoTong University, Shanghai Jiao Tong University

  • Yuting Tan

    Department of Physics and NHMFL, Florida State University, School of Physics, Sun Yat-sen Univeristy

  • Tianyu Zhang

    School of Physics and Astronomy, Shanghai Jiao Tong University

  • Tao Zou

    Department of Physics and Astronomy, Michigan State University

  • Antonio M. dos Santos

    Oak Ridge National Laboratory, Quantum Condensed Matter Division, Oak Ridge National Laboratory

  • Jin Hu

    University of Arkansas, Department of Physics and Engineering Physics, Tulane University, Department of Physics, University of Arkansas

  • Dao-Xin Yao

    School of Physics, Sun Yat-Sen University, China, Physics, Sun-Yat sen University, School of Physics, Sun Yat-sen Univeristy

  • Zhiqiang Mao

    Pennsylvania State University, Physics, Pennsylvania State University, Department of Physics and Engineering Physics, Tulane University, Physics and Engineering Physics, Tulane University, Tulane University

  • Xianglin Ke

    Department of Physics and Astronomy, Michigan State University, Michigan State Univ