Longitudinal spin susceptibility and spin dynamics of field-induced spin-density waves in Bechgaard salts

Making use of a Green’s function describing field-induced spin-density waves (FISDW’s) in Bechgaard salts, we calculate the longitudinal spin susceptibility. We find that the longitudinal susceptibility has a pole at ${\omega }^2$=(1-Ū)$v_F^2$ $q^2$ at all temperatures, which describes the longitudinal spin wave. Here Ū is the dimensionless Coulomb energy. Furthermore, the static spin susceptibility is independent of temperature. The spin dynamics of a FISDW are also considered. We predict magnetic solitons in FISDW’s.