Magnetic Interaction in a 2-D Electron Gas
When I came to the University of Pittsburgh for a sabbatical half year in 1962, I had just completed a study of the de Haas-van Alphen (dHvA) effect in copper, silver and gold . The main purpose of the study was to determine the Fermi surfaces (FS) of the metals, but I also found some peculiar features of the dHvA oscillations which could be plausibly interpreted if it was supposed that the electrons ‘perceived’ the magnetic field as B rather than H. Ordinarily, the difference 4πM between B and H is too small to make any appreciable difference, but if the oscillations are sufficiently strong to make 4πdM/dB ~ 1, there is a kind of feed-back effect, which has come to be known as magnetic interaction (MI) and which can significantly modify the form of the oscillations. I consulted Ted Holstein about this problem and asked him if it was possible to prove by microscopic theory that the relevant field was indeed B rather than H. After quite a short while he told me that within the Hartree approximation he could give such a proof, but he had some reservations and it was only 11 years later that he published a detailed analysis in collaboration with NORTON and PINCUS . In the meantime PIPPARD  had given a thermodynamic argument to show that B rather than H was the relevant field. Since its discovery over 20 years ago MI has been found to have a variety of interesting consequences and many of these have been demonstrated experimentally; a detailed account is available in two recent reviews [4,5].
KeywordsFermi Surface Magnetic Interaction Landau Level Quantum Hall Effect Relevant Field
Unable to display preview. Download preview PDF.
- 4.A.B. Pippard: In Electrons at the Fermi Surface, ed. by M. Springford (Cambridge University Press 1980) chap.4Google Scholar
- 13.I. Privorotskii: Thermodynamic Theory of Domain Structures (John Wiley & Sons, New York, Toronto 1976)Google Scholar
- 14.I.D. Vagner: private communicationGoogle Scholar
- 15.R.S. Markiewicz: preprint (1986) and private communicationGoogle Scholar