Unconventional density waves in organic conductors

Abstract

We present the theory of unconventional density waves (UDW) in quasi-one-dimensional electron systems. In UDW, the order parameter is a function of the wavenumber on the Fermi surface, like in unconventional superconductors. As a consequence, the UDW transition is not accompanied by static charge- or spin-density modulation, making it a possible candidate for the non-superconducting low temperature phase (LTP) of some of the α-(ET) 2 salts. We calculate the threshold electric field for non-linear conduction in UDW both with and without applied magnetic field. Based on comparison with data on non-linear conduction, we propose that the LTP in α-(ET) 2 salts is most likely an unconventional charge density wave (UCDW).