Magnetic-breakdown coupling between orbits of a low-electron-density system.

Abstract

We have studied by use of the de Haas--van Alphen effect a system of coupled orbits with low charge-carrier density: a single crystal of bromine-intercalated graphite. We have used a new method to determine the effective masses, as well as the de Haas--van Alphen amplitudes at zero temperature for a system with several close de Haas--van Alphen frequencies. We have shown that the Falicov-Stachowiak theory does not give quantitative agreement with our results. Nevertheless, it appears that the Pippard approximation of a network of coupled orbits with Landau numbers of about 15 still remains valid, but the probability of magnetic breakdown should be modified by taking into account the finite size of the magnetic-breakdown area.