Magic angles (lebed's and others), and the phase diagram of the bechgaard Salts

• Published in: Synthetic metals 1995-03, Vol.70 (1), p.731-734
• Main Authors: Danner, G.M., McKernan, S., Shi, X.D., Kang, W., Hannahs, S.T., Chaikin, P.M.
• Format: Article
• Language: English
• ISSN: 0379-6779; 1879-3290
• DOI: 10.1016/0379-6779(94)02632-9

We present transport data on the metallic and Field Induced Spin Density Wave phases of the Bechgaard Salts (TMTSF) 2PF 6 and (TMTSF) 2ClO 4. The a and c axis resistivities ( ρ xxand ρ zz) of these compounds have been measured for magnetic field rotations in the b-c planes (Lebed geometry) and striking resistance dips are observed at magic angles. We examine the differences between the two materials and the status of our understanding of the Lebed resonances. We then investigate the resistivities for magnetic fields rotated in the a-c plane. In this case we find a new set of resonances which for the first time allow direct measurements of the Fermi surface parameters of quasi-one-dimensional metals. Extending ρ xxand ρ zz measurements to 30 Tesla we have found that the phase boundary for the FISDW in (TMTSF) 2ClO 4 is most easily investigated by temperature dependent studies of ρ zz at high field. We find a new phase below a nearly temperature independent and we discuss some of the properties of this phase.