J. Phys. IV France
Volume 114, April 2004
Page(s) 35 - 40

J. Phys. IV France
114 (2004) 35
DOI: 10.1051/jp4:2004114006

Influence of charge order on the ground states of TMTTF molecular salts

W. Yu1, F. Zamborszky1, 2, B. Alavi1, A. Baur3, C.A. Merlic3 and S.E. Brown1

1  Department of Physics, UCLA, Los Angeles, CA 90095, USA
2  Los Alamos National Laboratory, Los Alamos, NM 87545, USA
3  Department of Chemistry and Biochemistry, UCLA, Los Angeles, CA 90095, USA

(TMTTF)2AsF6 and (TMTTF)2SbF6 are both known to undergo a charge ordering phase transition, though their ground states are different. The ground state of the first is Spin-Peierls, and the second is an antiferromagnet. We study the effect of pressure on the ground states and the charge-ordering using 13C NMR spectroscopy. The experiments demonstrate that the the CO and SP order parameters are repulsive, and consequently the AF state is stabilized when the CO order parameter is large, as it is for (TMTTF)2SbF6. An extension of the well-known temperature/pressure phase diagram is proposed. Key words. Organic conductors, charge order, spin-Peierls, antiferromagnet, high-pressure

© EDP Sciences 2004