抄録
We report a 35Cl NQR investigation into the neutral–ionic (NI) phase transition in DMTTF-QCl4 (4,4′-dimethyltetrathiafulvalene-p-chloranil), the end material of the family containing an NI quantum transition system. Four distinct lines with comparable intensities were observed well below Tc=65 K; this observation is consistent with the antiferroelectric nature of the ionic phase. The temperature dependences of the spectral shift and splitting below Tc are moderate in contrast with the case of TTF-QCl4. Low-energy charge-lattice fluctuations are observed around Tc as a drastic increase of 1⁄T1, allowing the observation of the quantum fluctuations in a chemically substituted complex. An analysis of the NQR spectra yields detailed temperature variations in the charge transfer and the concomitant lattice distortion around the NI transition.
