Interaction effect on the De Haas-van Alphen oscillations

A new formula which gives the many-body effects on the De Haas-van Alphen oscillations is presented. The oscillating susceptibility consists of sine and cosine terms. The amplitude of the sine oscillations is decreased by the exchange interaction and by the collective interaction, the latter causing a dependence on field strength. The cosine oscillations are enhanced but are smaller than the sine oscillations. The difference in the field dependences of these two types of oscillations will introduce a field-dependent amplitude when the two are combined. The frequency of the oscillations is not affected by the interaction. In addition to the oscillating susceptibility, the internal energy is also determined.