Stability of the spin density wave phases in (TMTSF)2ClO4 : quantized nesting effect

Abstract

The stability of the SDW phases in (TMTSF)2ClO4 can be interpreted by simple arguments of anisotropic Fermi surfaces nesting : first, we show that anion ordering, by introducing new Bragg's reflexions, perturbs the nesting and lowers the SDW stability. Then, we improve Gor'kov and Lebed's argument on the effect of a magnetic field on nesting by allowing the wave vector Q(H) to adapt to the field so that nesting is quantized. We predict that H induces a succession of SDW phases with Q(H) varying linearly, separated by first order transitions with Q(H) discontinuities. At low T, the Hall voltage is constant within in SDW phase, as in the Quantized Hall Effect This is in agreement with the Hall effect data.