J. Phys. IV France
Volume 12, Numéro 9, November 2002
Page(s) 139 - 144

J. Phys. IV France
12 (2002) Pr9-139
DOI: 10.1051/jp4:20020380

Influence of charge order on the ground state of TMTTF conductors

F. Zamborszky1, 2, W. Yu2, W. Raas2, S.E. Brown2, B. Alavi2, C.A. Merlic3, A. Baur3, S. Lefebvre2 and P. Wzietek4

1  Department of Physics and Astronomy, UCLA, Los Angeles, CA 90095-1547, U.S.A.
2  Los Alamos National Laboratory, Los Alamos, NM 87545, U.S.A.
3  Department of Chemistry and Biochemistry, UCLA, Los Angeles, CA 90095-1569, U.S.A.
4  Laboratoire de Physique des Solides, URA 2 du CNRS, Université Paris-Sud, bâtiment 510, 91405 Orsay, France

Properties of the charge-ordered (CO) phase for the representative salt (TMTTF) 2AsF 6 are determined using 13C and 75As nuclei as probes. The charge disproportionation ratio is found to be at least 3:1 at temperatures below the transition temperature T $_{\rm CO}$. At lower temperatures, the material undergoes a second transition to a singlet ground state. Investigations of the relative stability of the two orders under applied pressure reveal that the two orders compete. The phase diagram consists of a region of coexistence and a tetracritical point.

© EDP Sciences 2002