de Haas-van Alphen effect and quantum oscillations as a function of temperature in correlated insulators

We theoretically study a model of excitonic insulators which show de Haas-van Alphen oscillations as well as periodic dependence of the magnetization on inverse temperature. The insulating behavior is due to the Coulomb interaction driven hybridization of fermions at the crossing point of their energy bands. We show that the leading contribution to the oscillations at small magnetic fields is due to the oscillatory dependence of the hybridization gap on the magnetic field. In order to see this, the hybridization is derived from a self-consistent nonlinear equation. We show that the amplitude of the de Haas-van Alphen is oscillating with inverse temperature with a period defined by a combination of the hybridization gap and magnetic field. Moreover, we predicted that the amplitude must vanish at a particular field proportional to the hybridization gap.