Anisotropic superconductivity of quasi-one-dimensional electrons in magnetic field

We study theoretically the transition temperature T-c(H) of a quasi-one-dimensional anisotropic superconductor in a magnetic field, which is thought to be realized in organic conductors, (TMTSF)(2)X. In the weak field limit, -dH(c2)/dT for the anisotropic singlet is shown to be root 3 times larger than that for the anisotropic triplet in the case of attractive interaction of electrons at nearest-sites along the c axis and magnetic field along the b axis. In the strong field region the transition temperature for spin-triplet is restored to zero field critical temperature while the anisotropic spin-singlet is suppressed by the Zeeman effect. There should be transition from anisotropic singlet to anisotropic triplet as the magnetic field is increased.