Fig. 3: Lattice distortion and real space image of the superconducting order parameter.
Purple dashed lines below Tnem indicate the high-temperature atomic positions. The lattice distortion is strongly exaggerated. Arrows in the nematic phase indicate the directions of the thermal expansion measurements. In the latter, strong superconducting fluctuations break the discrete lattice symmetry without broken U(1) symmetry and superconducting coherence. A globally coherent superconducting state only sets in at the superconducting transition temperature Tc.
