论文标题
金属性和高$ T_C $超导性的高压阶段$ _ {0.89} $ S $ _ {0.11} $
Collapse of Metallicity and High-$T_c$ Superconductivity in the High-Pressure phase of FeSe$_{0.89}$S$_{0.11}$
论文作者
论文摘要
我们使用运输和隧道二极管振荡器研究研究了基于铁的超导体FESE $ _ {0.89} $ s $ _ {0.11} $的高压阶段。我们构建了详细的压力温度相图，表明在列前相外，超导临界温度达到最低，然后迅速增强到4 GPA以上的40 K。电阻率数据揭示了非Fermi液体行为的粉丝样结构的签名，这可能表明存在于4.3 GPA约4.3 GPA的超导穹顶下方的假定量子临界点。进一步增加压力，零场电阻率会发展出非金属温度依赖性，并且超导转变显着扩大。最终，尽管连续有限的超导过渡温度，该系统仍无法达到完全零的抗性状态，并且在低温下的任何剩余电阻都非常依赖于电流。我们的结果表明，高压，高$ T_C $相位的铁葡萄糖生成层非常脆弱，并且对压力培养基，细胞设计和样品厚度的单轴效应非常敏感，这可能会触发一阶过渡。可以理解这些高压区域，假设由伴随的电子和结构不稳定性引起的真实空间相分离。
We investigate the high-pressure phase of the iron-based superconductor FeSe$_{0.89}$S$_{0.11}$ using transport and tunnel diode oscillator studies. We construct detailed pressure-temperature phase diagrams that indicate that outside of the nematic phase, the superconducting critical temperature reaches a minimum before it is quickly enhanced towards 40 K above 4 GPa. The resistivity data reveal signatures of a fan-like structure of non-Fermi liquid behaviour which could indicate the existence of a putative quantum critical point buried underneath the superconducting dome around 4.3 GPa. Further increasing the pressure, the zero-field electrical resistivity develops a non-metallic temperature dependence and the superconducting transition broadens significantly. Eventually, the system fails to reach a fully zero-resistance state despite a continuous finite superconducting transition temperature, and any remaining resistance at low temperatures becomes strongly current-dependent. Our results suggest that the high-pressure, high-$T_c$ phase of iron chalcogenides is very fragile and sensitive to uniaxial effects of the pressure medium, cell design and sample thickness which can trigger a first-order transition. These high-pressure regions could be understood assuming a real-space phase separation caused by concomitant electronic and structural instabilities.
