CDW instability in the 2:l organic conductor (FA)2PF6

V. ILAKOVAC; S. RAVY; J.P. POUGET; W. RIESS; W. BRÜTTING; M. SCHWOERER

doi:doi:10.1051/jp4:1993227

Numéro		J. Phys. IV France Volume 03, Numéro C2, Juillet 1993 International Workshop on Electronic Crystals ECRYS - 93


Page(s)		C2-137 - C2-140
DOI		https://doi.org/10.1051/jp4:1993227

International Workshop on Electronic Crystals
ECRYS - 93

J. Phys. IV France 03 (1993) C2-137-C2-140
DOI: 10.1051/jp4:1993227

CDW instability in the 2:l organic conductor (FA)₂PF₆

V. 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

Abstract
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 T_c ≈ 200K, breaks the face center Bravais lattice symmetry. The lower one, of the Peierls type, corresponds to the 3D ordering of quasi-1D 2k_F 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.