Eur. Phys. J. B 21, 31-37 (2001)
https://doi.org/10.1007/s100510170209

Unconventional field and angle dependences of the Shubnikov-de Haas oscillations spectra in the quasi two-dimensional organic superconductor (BEDO-TTF)₂ReO₄H₂O

¹ Laboratoire de Physique de la Matière Condensée (UMR-CNRS 5830) , Laboratoire National des Champs Magnétiques Pulsés, INSA, 135 avenue de Rangueil, 31077 Toulouse, France
² Institute of Problems of Chemical Physics, RAS, Chernogolovka, MD 142432, Russian Federation
³ Institut de Ciencia de Materiales de Barcelona, Campus de la UAB, 08193 Bellaterra, Spain
⁴ University of Oxford, Department of Physics, Clarendon Laboratory, OX1 3PU, UK

Corresponding author: ^a audouard@insa-tlse.fr

Received: 22 August 2000
Revised: 20 December 2000
Published online: 15 May 2001

Abstract

We report on the inter-layer oscillatory conductance of the two-dimensional organic superconductor (BEDO-TTF)₂ReO₄H₂O measured in static and pulsed magnetic fields of up to 15 and 52 T, respectively. In agreement with previous in-plane studies, two Shubnikov-de Haas oscillation series linked to the two electron and the hole orbits are observed. The influence of the magnitude and orientation of the magnetic field with respect to the conducting plane is studied in the framework of the conventional two- and three-dimensional Lifshits-Kosevich (LK) model. Deviations of the data from this model are observed in low fields strongly tilted with respect to the normal to the conducting plane. In this latter case, the observed behaviour is consistent with an unexplained lowering of the cyclotron effective mass. At high magnetic field, the oscillatory data could have been compatible with the occurrence of a magnetic breakdown orbit built from the hole and electron orbits. However, the increase of the cyclotron effective mass, linked to the electron orbits, as the magnetic field increases above ~12 T is consistent with a field-induced phase transition. In the lower field range, where the conventional LK model holds, the analysis of the angle dependence of the oscillations amplitude suggests significant renormalisation of the effective Landé factor.