X-Ray-Diffuse-Scattering Evidence for a Phase Transition in Tetrathiafulvalene Tetracyanoquinodimethane (TTF-TCNQ)

Abstract
X-ray-diffuse-scattering measurements of tetrathiafulvalene tetracyanoquinodimethane (TTF-TCNQ) show structural evidence of a phase transition. The low-temperature three dimensional superlattice (2a×3.7b×Xc) is found to be preceded above 40 K by one-dimensional fluctuations or a one-dimensional distortion visible up to 55 K.