ECRYS - 93
J. Phys. IV France 03 (1993) C2-137-C2-140
CDW instability in the 2:l organic conductor (FA)2PF6V. ILAKOVAC1, S. RAVY1, J.P. POUGET1, W. RIESS2, W. BRÜTTING2 and M. SCHWOERER2
1 Laboratoire de Physique des Solides, URA CNRS 02, Université Paris-Sud, 91405 Orsay, France
2 Phys. Inst. and BIMF, Universität Bayreuth, 8580 Bayreuth, Germany
We present an X-ray diffuse scattering study of the fluoranthene radical cation salt (FA)2PF6, where FA is the fluoranthene molecule, C16H10. Below room temperature this salt undergoes two successive structural phase transitions. The upper one, at Tc ≈ 200K, breaks the face center Bravais lattice symmetry. The lower one, of the Peierls type, corresponds to the 3D ordering of quasi-1D 2kF charge density waves (CDW) at Tp ≈ 180K, temperature below which collective transport phenomena are observed. We compare this material to the Bechgaard salts (TMTS(T)F)2X, of very similar stack structure but where a Peierls CDW ground state is not stabilized.
© EDP Sciences 1993