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

Abstract

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 study this hybridization self-consistently and recover known results by A. Allocca and N. Cooper, SciPost Phys. {\bf 12}, 123 (2022). In addition to known results, we show that the hybridization gap decreases with the magnetic field which corresponds to the diamagnetism. Furthermore, 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. We analytically obtain the position and the height of the first and dominant peak of these oscillations.