High-Tc Phase of PrO0.5F0.5BiS2 single crystal induced by uniaxial pressure.

We demonstrated a pressure-induced phase transition from a low-Tc phase (3.5 K) to a high-Tc phase (8.7 K) in single crystalline PrO0.5F0.5BiS2. The high-Tc phase is easily observed even at 0.7 GPa by uniaxial pressure obtained from a geometric effect of a single crystal with an extremely thin thickness. For this phase transition, superconducting anisotropy and the coherence length along the c axis change from γ = 20 to 9.3 and from ξc = 0.56 to 0.71 nm, respectively. It is suggested that a shrinkage in the c lattice constant by applied uniaxial pressure enhances the three dimensionality in the superconducting state. [ABSTRACT FROM AUTHOR]