We report the successful synthesis of ${\mathrm{FeSe}}_{1-x}{\mathrm{S}}_x$ single crystals with $x$ ranging from 0 to 1 via a hydrothermal method. A complete phase diagram of ${\mathrm{FeSe}}_{1-x}{\mathrm{S}}_x$ has been obtained based on resistivity and magnetization measurements. The nematicity is suppressed with increasing $x$, and a small superconducting dome appears within the nematic phase. Outside the nematic phase, the superconductivity is continuously suppressed and reaches a minimum $T_{\text{c}}$ at $x$ = 0.45; beyond this point, $T_{\text{c}}$ slowly increases until $x$ = 1. Intriguingly, an anomalous resistivity upturn with a characteristic temperature $T^{*}$ in the intermediate region of $0.31\le x\le 0.71$ is observed. $T^{*}$ shows a domelike behavior with a maximum value at $x$ = 0.45, which is opposite the evolution of $T_{\text{c}}$, indicating competition between $T^{*}$ and superconductivity. The origin of $T^{*}$ is discussed in detail. Furthermore, the normal state resistivity evolves from non-Fermi-liquid to Fermi-liquid behavior with S doping at low temperatures, accompanied by a reduction in electronic correlations. Our study addresses the lack of single crystals in the high-S doping region and provides a complete phase diagram, which will promote the study of relations among nematicity, superconductivity, and magnetism.

• Received 17 October 2020
• Revised 28 February 2021
• Accepted 23 March 2021

DOI:https://doi.org/10.1103/PhysRevB.103.144501