An analysis of our measurements of the b-axis expansivity b of tetrathiafulvalene-tetracyanoquinodimethane (TTF-TCNQ) within the Debye approximation suggests an unexpectedly high effective Debye temperature (b=20030 K) and a large anharmonicity (=51.5) for the low-lying b-axis polarized acoustic phonons. These values for and b indicate substantial softening of the lattice above 100 K and also suggest an expansivity contribution from intramolecular vibrational modes. No anomalous length changes were observed in the region of the metal-semiconductor transition (45-65 K) to within LbLb 3×10-5.
All Science Journal Classification (ASJC) codes
- Condensed Matter Physics