Europhys. Lett.
Volume 71, Number 5, September 2005
Page(s) 783 - 789
Section Condensed matter: electronic structure, electrical, magnetic, and optical properties
Published online 29 July 2005
Europhys. Lett., 71 (5), pp. 783-789 (2005)
DOI: 10.1209/epl/i2005-10145-8

Magnetic oscillations in a two-dimensional network of compensated electron and hole orbits

A. Audouard1, D. Vignolles1, E. Haanappel1, I. Sheikin2, R. B. Lyubovskii3 and R. N. Lyubovskaya3

1  Laboratoire National des Champs Magnétiques Pulsés (UMR CNRS-UPS-INSA 5147) 143 avenue de Rangueil, 31432 Toulouse cedex 4, France
2  Grenoble High Magnetic Field Laboratory, CNRS BP 166, 38042 Grenoble Cedex 9, France
3  Institute of Problems of Chemical Physics, Russian Academy of Sciences Chernogolovka, Moscow oblast, 142432 Russia

received 14 March 2005; accepted in final form 29 June 2005
published online 29 July 2005

The Fermi surface of the quasi-two-dimensional (2D) organic metal $\chem{(ET)_8Hg_4Cl_{12}}$ $\chem{(C_6H_5Br)_2}$ can be regarded as a 2D network of compensated electron and hole orbits coupled by magnetic breakthrough. Simultaneous measurements of the interlayer magnetoresistance and magnetic torque have been performed for various directions of the magnetic field up to 28$\un{T}$ in the temperature range from 0.36$\un{K}$ to 4.2$\un{K}$. Magnetoresistance and de Haas-van Alphen (dHvA) oscillations spectra exhibit frequency combinations typical of such a network. Even though some of the observed magnetoresistance oscillations cannot be interpreted on the basis of either conventional Shubnikov-de Haas oscillations or quantum interference, the temperature and magnetic field (both orientation and magnitude) dependence of all the Fourier components of the dHvA spectra can be consistently accounted for by the dHvA effect on the basis of the Lisfhitz-Kosevich formula. This behaviour is at variance with that currently reported for compounds illustrating the linear chain of coupled orbits model.

71.18.+y - Fermi surface: calculations and measurements; effective mass, g factor.
72.15.Gd - Galvanomagnetic and other magnetotransport effects.
71.20.Rv - Polymers and organic compounds.

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