Maximizing by tuning nematicity and magnetism in FeSeS superconductors
松浦 康平*; 水上 雄太*; 新井 佑基*; 杉村 優一*; 前島 尚行*; 町田 晃彦*; 綿貫 徹*; 福田 竜生 ; 矢島 健*; 廣井 善二*; Yip, K. Y.*; Chan, Y. C.*; Niu, Q.*; 細井 優*; 石田 浩祐*; 向笠 清隆*; 笠原 成*; Cheng, J.-G.*; Goh, S. K.*; 松田 祐司*; 上床 美也*; 芝内 孝禎*
Matsuura, Kohei*; Mizukami, Yuta*; Arai, Yuki*; Sugimura, Yuichi*; Maejima, Naoyuki*; Machida, Akihiko*; Watanuki, Tetsu*; Fukuda, Tatsuo; Yajima, Takeshi*; Hiroi, Zenji*; Yip, K. Y.*; Chan, Y. C.*; Niu, Q.*; Hosoi, Suguru*; Ishida, Kosuke*; Mukasa, Kiyotaka*; Kasahara, Shigeru*; Cheng, J.-G.*; Goh, S. K.*; Matsuda, Yuji*; Uwatoko, Yoshiya*; Shibauchi, Takasada*
A fundamental issue concerning iron-based superconductivity is the roles of electronic nematicity and magnetism in realising high transition temperature (). To address this issue, FeSe is a key material, as it exhibits a unique pressure phase diagram involving nonmagnetic nematic and pressure-induced antiferromagnetic ordered phases. However, as these two phases in FeSe have considerable overlap, how each order affects superconductivity remains perplexing. Here we construct the three-dimensional electronic phase diagram, temperature () against pressure () and iso-valent S-substitution (), for FeSeS. By simultaneously tuning chemical and physical pressures, against which the chalcogen height shows a contrasting variation, we achieve a complete separation of nematic and antiferromagnetic phases. In between, an extended nonmagnetic tetragonal phase emerges, where shows a striking enhancement. The completed phase diagram uncovers that high- superconductivity lies near both ends of the dome-shaped antiferromagnetic phase, whereas remainslow near the nematic critical point.