Anomalous in-plane anisotropy of the onset of superconductivity in (TMTSF)2ClO4

We report the magnetic-field amplitude and field-angle dependence of the superconducting onset temperature Tconset of the organic superconductor (TMTSF)2ClO4 in magnetic fields H accurately aligned to the conductive ab' plane. We revealed that the rapid increase of the onset fields at low temperatures occurs both for H//b' and H//a, irrespective of the carrier confinement. Moreover, in the vicinity of the Pauli-limiting field, we report a shift of a principal axis of the in-plane field-angle dependence of Tconset. This feature may be related to an occurrence of Fulde-Ferrell-Larkin-Ovchinnikov phases.

Polar plot of Tc-onset of (TMTSF)2ClO4
Fig.1: Polar-plot of superconducting "onset" temperature of (TMTSF)2ClO4.

This result is published in Physical Review Letters.

Paper

Shingo Yonezawa, S. Kusaba, Y. Maeno, P. Auban-Senzier, C. Pasquier, K. Bechgaard, and D. Jérome
Anomalous In-Plane Anisotropy of the Onset of Superconductivity in (TMTSF)2ClO4
Phys. Rev. Lett. 100 11 117002 Mar. 2008