We point out that (TMTSF)2PF6 compound at P ≃ 6 kbar is possibly a triplet superconductor with the vector order parameter d = (dx ≠ 0, dy ,dz = 0). It corresponds to an anisotropic spin susceptibility in a superconducting state: χb′(z) = χ0, χa(x) ≠ χ0, where χ0 is its value in a metallic phase. (Here, the spin quantization axis, z, is parallel to the easy axis, b′, of an antiferromagnetic SDW phase existing at P = 0). It is shown that the suggested order parameter can explain why the upper critical field along b′-axis (I.J. Lee, M.J. Naughton, G. Danner, and P.M. Chaikin, Phys. Rev. Lett. 78, 3555 (1997)) exceeds all paramagnetic limiting fields (including that for a non-uniform superconductivity) whereas the upper critical field along the a-axis is restricted by the Pauli paramagnetic effects. The triplet order parameter is consistent with the earlier results on a destruction of superconductivity by nonmagnetic impurities and the absence of the Hebel-Slichter peak in the NMR data as well as with the recent Knight shift measurements by S. Brown et al and by I. J. Lee et al.
|Original language||English (US)|
|Number of pages||2|
|Journal||Physica C: Superconductivity and its Applications|
|Issue number||PART 2|
|Publication status||Published - 2000|
ASJC Scopus subject areas
- Condensed Matter Physics