Dresden 2014 – scientific programme

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TT: Fachverband Tiefe Temperaturen

TT 80: Low-Dimensional Systems - Poster Session

TT 80.11: Poster

Wednesday, April 2, 2014, 15:00–19:00, P2

In-plane dependence of the FFLO state in the quasi-2D organic superconductor β″-(ET)₂SF₅CH₂CF₂SO₃ — •R. Beyer¹, E. Green¹, J.A. Schlueter², R. Zahn¹, S. Jahns³, G. Zwicknagl³, and J. Wosnitza¹ — ¹Hochfeld-Magnetlabor (HLD), Helmholtz-Zentrum Dresden- Rossendorf (HZDR), Germany — ²Materials Science Division, Argonne National Laboratory, USA — ³Institute for Mathematical Physics, TU Braunschweig, Germany

In recent years, clear thermodynamic evidence for FFLO superconductivity in the organic superconductor κ-(ET)₂Cu(NCS)₂, where ET stands for bisethylenedithio-tetrathiafulvalene, was found [1]. Performing high-resolution specific-heat measurements, we found as well evidence for the FFLO state in β″-(ET)₂SF₅CH₂CF₂SO₃, when the magnetic field is applied parallel to the superconducting ET layers [2]. Theoretical studies predict a strong in-plane critical field anisotropy of the FFLO phase. As a consequence of the low-dimensional character of the electronic structure, the calculations predict pronounced fluctuation effects which are reflected in substantial broadening of the superconducting transition. Therefore, we carried out specific-heat measurements with three different in-plane field orientations. The phase diagram with the pronounced upturn around 9.5 Tesla is independent of the in-plane field orientation. This points to an FFLO wave vector, that is fixed to a certain in-plane direction.
R. Lortz et al., Phys. Rev. Lett. 99, 187002 (2007)
R. Beyer et al., Phys. Rev. Lett. 109, 027003 (2012)