Crossover of Superconductivity across the antiferromagnetic end point in FeSe$_{\rm 1-x}$S$_{\rm x}$ under pressure

Kiyotaka Miyoshi; Takanobu Nakatani; Yumi Yamamoto; Takumi Maeda; Daichi Izuhara; Ikumi Matsushima

doi:10.1103/lxzc-l3md

paper

Crossover of Superconductivity across the antiferromagnetic end point in FeSe $_{1 - x}$ S $_{x}$ under pressure

arXiv:2505.04156 · doi:10.1103/lxzc-l3md

Abstract

Temperature-pressure ( $T$ - $P$ ) phase diagrams of FeSe $_{1 - x}$ S $_{x}$ were investigated by the measurements of dc magnetization ( $M$ ) and electrical resistivity ( $ρ$ ) under pressure, using single crystal specimens with $x$ =0.04, 0.08 and 0.13. For all specimens, the $M$ ( $T$ ) curves under pressure near the end point of the antiferromagnetic (AFM) phase are found to show a two-step diamagnetic response, which can be described as the sum of two diamagnetic components $M_{1}$ ( $T$ ) and $M_{2}$ ( $T$ ), indicating that two superconducting (SC) phases with different $T_{c}$ values coexist within a pressure range of $Δ$ $P$ $\sim$ 1 GPa. Moreover, the pressure dependence of the amplitudes of $M_{1}$ ( $T$ ) and $M_{2}$ ( $T$ ) indicates a continuous transfer of the volume fraction between the two SC phases. These behaviors suggest that a crossover of superconductivity occurs in conjunction with the emergence of AFM phase and imply that the SC phases inside and outside the AFM phase could have different origins.

6 pages, 3 figures, to appear in Phys. Rev. B

Crossover of Superconductivity across the antiferromagnetic end point in FeSe1−x​Sx​ under pressure

Abstract

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Crossover of Superconductivity across the antiferromagnetic end point in FeSe $_{1 - x}$ S $_{x}$ under pressure