Correlation between crystal structure and superconductivity in LaO0.5F0.5BiS2

•The LaO0.5F0.5BiS2 superconductor's crystal lattice was tuned by various annealing conditions.•Superconducting properties were obviously changed by tuning the crystal lattice.•Superconductivity could be related to the uniaxial strain along the c axis.

Correlation between crystal structure and superconducting properties of the BiS2-based superconductor LaO0.5F0.5BiS2 was investigated. We have prepared LaO0.5F0.5BiS2 polycrystalline samples with various lattice constants. It was found that high-pressure annealing generated uniaxial strain along the c axis. Further, the highly-strained sample showed higher superconducting properties. We concluded that the uniaxial strain along the c axis was positively linked with the enhancement of superconductivity in the LaO1−xFxBiS2 system.