Anomalous Nature of Neutral-to-Ionic Phase Transition in Tetrathiafulvalene-Chloranil

J. B. Torrance; A. Girlando; J. J. Mayerle; J. I. Crowley; V. Y. Lee; P. Batail; S. J. LaPlaca

doi:10.1103/PhysRevLett.47.1747

Anomalous Nature of Neutral-to-Ionic Phase Transition in Tetrathiafulvalene-Chloranil

J. B. Torrance, A. Girlando, J. J. Mayerle, J. I. Crowley, V. Y. Lee, P. Batail, and S. J. LaPlaca

Phys. Rev. Lett. 47, 1747 – Published 14 December 1981

Abstract

A phase transition starting at 84 K and indicated by a marked color change of the sample has been found in the organic insulator tetrathiafulvalene-chloranil. Optical, infrared, and Raman measurements indicate that this is a reversible transition from a nominally neutral (N) solid to a nominally ionic (I) salt. Surprisingly, the N-I transition is not first order, but occurs over a broad temperature region (∼30 K), in which there is a coexistence of N and I molecules.

Received 23 June 1981

DOI:https://doi.org/10.1103/PhysRevLett.47.1747

Authors & Affiliations

J. B. Torrance, A. Girlando^*, J. J. Mayerle, J. I. Crowley, V. Y. Lee, and P. Batail^†

IBM Research Laboratory, San Jose, California 95193

S. J. LaPlaca

IBM Watson Research Center, Yorktown Heights, New York 10598

^*Permanent address: University of Padova, I-35100 Padova, Italy.
^†Permanent address: Laboratoire de Cristallochimie, Université de Rennes, F-35042 Rennes, France.