Hydrothermal synthesis and complete phase diagram of FeSe${}_{1-x}$S${}_x$ $(0\le x\le 1)$ single crystals

Abstract

We report the successful synthesis of FeSe${}_{1-x}$S${}_x$ single crystals with $x$ ranging from 0 to 1 via a hydrothermal method. A complete phase diagram of FeSe${}_{1-x}$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 $T_c$ at $x$ = 0.45; beyond this point, $T_c$ slowly increases until $x$ = 1. Intriguingly, an anomalous resistivity upturn with a characteristic temperature $T^{\ast }$ in the intermediate region of $0.31\le x\le 0.71$ is observed. $T^{\ast }$ shows a dome-like behavior with a maximum value at $x$ = 0.45, which is opposite the evolution of $T_c$, indicating competition between $T^{\ast }$ and superconductivity. The origin of $T^{\ast }$ 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.

8 pages, 3 figures