Investigations of Fermi Surfaces and Effective Masses of the Organic Superconductors (BEDO-TTF)_{2}ReO_{4}(H_{2}O) and κ-(BEDT-TTF)_{2}I_{3} by Shubnikov-de Haas and de Haas-van Alphen Measurements

• Authors: D. Schweitzer , E. Balthes , S. Karlich , I. Heinen , H.J. Keller , W. Strunz , W. Biberacher , A.G.M. Jansen , E. Steep
• Languages of publication: EN

Abstracts

EN

The Fermi surfaces and effective masses of (BEDO-TTF)_{2}ReO_{4}(H_{2}0) and κ-(BEDT-TTF)_{2}I_{3} were investigated by Shubnikov–de Haas (SdH) and de Haas–van Alphen (dHvA) measurements in magnetic fields up to 27 T in the temperature range from 0.5 K to 4.2 K. Two small closed pockets (0.7% and 1.5% of the first Brillouin zone) are observed in (BEDO-TTF)_{2}ReO_{4}(H_{2}0) corresponding very well with two cross-sectional areas of the Fermi surfaces obtained for a hole and an electron pocket from tight binding calculations. In contrast, in κ-(BEDT-TTF)_{2}I_{3} two rel­atively large closed sections (13% and 85% of the first Brillouin zone) of the Fermi surfaces are observed, again confirming the tight binding calcu­lations. For κ-(BEDT-TTF)_{2}I_{3} in magnetic fields above 12 T the effective mass for the larger orbit, as obtained from the temperature dependence of the SdH-oscillation amplitudes, is magnetic field dependent as long as the field is arranged perpendicular to the conducting planes (Θ = 0°). In con­trast, from dHvA measurements - which were performed by turning the magnetic field by 27° with respect to the SdH experiments - the observed effective mass is field independent. We suppose that the occurrence of anyons at temperatures below 1 K and in fields above 12 T might be the reason for the observed field dependence of the effective mass in the SdH investigations under the special angle 0°.

Keywords

EN

71.25.Jd; 71.25.Hc; 74.70.Kn

• Publisher: Institute of Physics, Polish Academy of Sciences
• Journal: Acta Physica Polonica A
• Year: 1995
• Volume: 87
• Issue: 4-5
• Pages: 749-759

Dates

published

1995-04

Contributors

author

D. Schweitzer

• 3. Physik. Institut, Universität Stuttgart, Pfaffenwaldring 57, 70550 Stuttgart, Germany

author

E. Balthes

• 3. Physik. Institut, Universität Stuttgart, Pfaffenwaldring 57, 70550 Stuttgart, Germany

author

S. Karlich

• 3. Physik. Institut, Universität Stuttgart, Pfaffenwaldring 57, 70550 Stuttgart, Germany

author

I. Heinen

• Anorg.-Chemisches Institut, Universität Heidelberg, Im Neuenheimer Feld 270, 69120 Heidelberg, Germany

author

H.J. Keller

• Anorg.-Chemisches Institut, Universität Heidelberg, Im Neuenheimer Feld 270, 69120 Heidelberg, Germany

author

W. Strunz

• Anorg.-Chemisches Institut, Universität Heidelberg, Im Neuenheimer Feld 270, 69120 Heidelberg, Germany

author

W. Biberacher

• Walther Meissner Institut, Walther-Meissner-Str. 8, 85748 Garching, Germany

author

A.G.M. Jansen

• High Magnetic Field Laboratory, MPI für Festkörperforschung, 38042 Grenoble Cedex 9, France

author

E. Steep

• High Magnetic Field Laboratory, MPI für Festkörperforschung, 38042 Grenoble Cedex 9, France