| Abstract Scope |
BiS2-based compounds, such as REOBiS2, feature a layered structure where conductive BiS2 layers alternate with insulating rare-earth oxide layers. While LaOBiS2 becomes superconductive at approximately 3 K through F ions substitution, recent research has shifted toward High-Entropy Alloy (HEA) type rare-earth sites. Specifically, the composition La0.20Ce0.20Pr0.20Nd0.20Sm0.20O0.5F0.5BiS2 has demonstrated improved transition temperatures (Tc) around 4.3 K.
Building on previous evidence that Pb or Sn substitution at the Bi site enhances performance in simpler compounds, this study investigates these effects within the HEA framework. Using a molten salt flux method, the researchers synthesized single crystals and characterized them via XRD, EDX, and resistivity measurements. Preliminary results show that Sn substitution in the HEA compound, specifically La0.20Ce0.20Pr0.20Nd0.20Sm0.20O0.4F0.6BiS2, further increases the superconducting transition temperature (Tconset) compared to the parent material. This research highlights elemental tuning at the Bi site as a vital strategy for optimizing superconductivity in complex high-entropy systems. |