Date of Original Version
We discuss recent high-field specific-heat measurements on the spin-Peierls compound tetrathiafulvalinium bis-cis-(1,2-perfluoromethylethylene-1-2-dithiolato)–gold [TTF-BDT(Au)]. An ordering anomaly can clearly be detected which defines a high-field phase boundary, despite some extraneous structure in the data apparently reflecting experimental limitations. The high-field phase boundary is in good quantitative agreement with the theory of Cross and Fisher. Further, the specific-heat data are in good agreement with earlier ac susceptibility data, the reliability of which as indicators of a phase transition has been somewhat open to doubt because pronounced relaxation effects in the high-field regime result in striking differences between χac and χdc. Some observations are made concerning the extent of hysteresis associated with the phase boundary between dimerized and high-field phases. Finally, the extensive experimental data are employed in several tests to determine the applicability of recent soliton theories.
J. C. Bonner, J. A. Northby, I. S. Jacobs, and L. V. Interrante. (1987). "High-field specific-heat and susceptibility measurements: Relevance to the spin-Peierls phase diagram and the validity of a soliton picture." Physical Review B, 35(4), 1791. Available at: http://dx.doi.org/10.1103/PhysRevB.35.1791