Theory of Coexisting Charge and Spin-Density Waves in (TMTTF)_2Br,   (TMTSF)_2PF_6 and alpha-(BEDT-TTF)_2MHg(SCN)_4
  Recent experiments indicate that the spin-density waves (SDWs) in (TMTTF)_2Br, (TMTSF)_2PF_6 and alpha-(BEDT-TTF)_2MHg(SCN)_4 are highly unconventional and coexist with charge-density waves (CDWs). We present a microscopic theory of this unusual CDW-SDW coexistence.   A complete understanding requires the explicit inclusion of strong Coulomb interactions, lattice discreteness, the anisotropic two-dimensional nature of the lattice, and the correct bandfilling within the starting Hamiltonian. 
S. Mazumdar, S. Ramasesha, R.T. Clay, D.K. Campbell