J. Phys. I France
Volume 6, Numéro 12, December 1996
Page(s) 1819 - 1936
DOI: 10.1051/jp1:1996190
J. Phys. I France 6 (1996) 1819-1936

Magnetic Oscillations in a Normal State of Organic Conductors: Many-Body Approach

A.G. Lebed

Institute for Materials Research, Tohoku University, Sendai 980-77, Japan and L.D. Landau Institute for Theoretical Physics, Russian Academy of Sciences, 117334 Moscow, 2 Kosygina St., Russia

(Received 26 April 1996, received in final form 27 June 1996, accepted 4 July 1996)

We argue that magnetic and angular oscillations observed in quasi-one-dimensional (Q1D) organic conductors represent a new type of many-body phenomena. The physical nature of such effects as "magic angles" in (TMTSF) 2ClO 4, (TMTSF) 2PF 6, and (DMET-TSeF) 2 AuCl 2 as well as "rapid magnetic oscillations" in (TMTSF) 2ClO 4 is shown to be beyond the standard theory of metals. Below we discuss an explanation of these phenomena which utilizes unusual many-body effect - a change of an effective dimensionality of electron-electron ("e-e") interactions with changing both a magnitude and a direction of a magnetic field. We show that some exotic transport properties of a metallic state can be interpreted in terms of these dimensional crossovers. We also demonstrate that magnetic field dependence of "e-e" interactions has to break Fermi liquid description of quasiparticles at high magnetic fields, $H\geq 25-30$ T. This leads to the appearance of strong forbidden oscillations of magnetic susceptibility, $\delta\chi/\chi_0\sim 1-10$ and magnetic moment, $\delta M/M_0\sim 0.1.$ All of the above mentioned unique properties of a metallic phase in (TMTSF) 2X and (DMET-TSeF)AuCl 2 allow us to call it an anomalous metallic phase.

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