Impact of nematicity on the relationship between antiferromagnetic fluctuations and superconductivity in ${{\mathrm{FeSe}}_{0.91}\mathrm{S}}_{0.09}$ under pressure

Journal Article · 06 May 2020 · Physical Review B

DOI: https://doi.org/10.1103/PhysRevB.101.180503 · OSTI ID:1617468

Rana, K.  ^[1]; Xiang, L.  ^[1]; Wiecki, P. ^[2]; Ribeiro, R. A.  ^[1]; Lesseux, G. G.  ^[1]; Böhmer, A. E. ^[2]; Bud'ko, S. L. ^[1]; Canfield, P. C. ^[1]; Furukawa, Y.  ^[1]

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1. Ames Lab., and Iowa State Univ., Ames, IA (United States)
2. Ames Lab., and Iowa State Univ., Ames, IA (United States); Karlsruhe Inst. of Technology (KIT) (Germany)

The sulfur-substituted FeSe system, ${\mathrm{FeSe}}_{1-x}{\mathrm{S}}_x$, provides a versatile platform for studying the relationship among nematicity, antiferromagnetism, and superconductivity. Herein, by nuclear magnetic resonance (NMR) and resistivity measurements up to 4.73 GPa on ${\mathrm{FeSe}}_{0.91}{\mathrm{S}}_{0.09}$, we established the pressure- ( $p$-) temperature ( $T$) phase diagram in which the nematic state is suppressed with pressure showing a nematic quantum phase transition (QPT) around $p=0.5\mathrm{GPa}$, two superconductivity (SC) regions separated by the QPT appear, and antiferromagnetic (AFM) phase emerges above $~3.3\mathrm{GPa}$. From the NMR results up to 2.1 GPa, AFM fluctuations are revealed to be characterized by the stripe-type wave vector which remains the same for the two SC regions. Furthermore, the electronic state is discovered to change in character from non-Fermi liquid to Fermi liquid around the nematic QPT and persists up to $~2.1\mathrm{GPa}$. In addition, although the AFM fluctuations correlate with $T_{\mathrm{c}}$ in both SC states, demonstrating the importance of the AFM fluctuations for the appearance of SC in the system, we found that, when nematic order is absent, $T_{\mathrm{c}}$ is strongly correlated with the AFM fluctuations whereas $T_{\mathrm{c}}$ weakly depends on the AFM fluctuations when nematic order is present. Our findings on ${\mathrm{FeSe}}_{0.91}{\mathrm{S}}_{0.09}$ were shown to be applied to the whole ${\mathrm{FeSe}}_{1-x}{\mathrm{S}}_x$ system and offer an insight into the relationship between AFM fluctuations and SC in Fe-based superconductors.

• Research Organization: Ames Laboratory (AMES), Ames, IA (United States)
• Sponsoring Organization: USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22). Materials Sciences & Engineering Division
• Grant/Contract Number: AC02-07CH11358
• OSTI ID: 1617468
• Report Number(s): IS-J 10,212
• Journal Information: Physical Review B, Journal Name: Physical Review B Journal Issue: 18 Vol. 101; ISSN 2469-9950; ISSN PRBMDO
• Publisher: American Physical Society (APS)Copyright Statement
• Country of Publication: United States
• Language: English