Possible triplet order parameter in a Q1D organic superconductor (TMTSF) 2PF 6
Abstract
We point out that (TMTSF) 2PF 6 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: χ b‧ ( z) = χ 0, χ a( x) ≠ χ 0, where χ 0 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.
- Publication:
-
Physica C Superconductivity
- Pub Date:
- November 2000
- DOI:
- 10.1016/S0921-4534(00)00943-6
- Bibcode:
- 2000PhyC..341.1699L