Triplet Superconductivity Order Parameter in AN Organic Superconductor (TMTSF)2PF6

We argue that an organic superconductor (TMTSF)₂PF₆ under pressure P = 6 kbar is a triplet superconductor^1,2 with a spin part of the triplet order parameter being d(k) = (d_x (k) ≠ 0, d_y (k) = 0, d_z (k) =0). We obtain these results by means of an analysis of the anisotropic experimental critical fields H_c2 (see I. J. Lee et al., Phys. Rev. Lett. 78, 3555 (1997)). By using symmetry arguments, we also discuss the most probably orbital part of the triplet order parameter in (TMTSF)₂PF₆. Our analysis is in accordance with the very recent Knight shift data obtained on (TMTSF)₂PF₆.