Mean-field study of quantum oscillations in two-dimensional Kondo insulators

Magnetic oscillations in strongly correlated insulating systems have garnered interest due to oscillations seemingly originating from the bulk, despite an anticipated gapped spectrum. We use the large-$N$ mean-field theory to study the behavior of normal and topological Kondo insulators under a magnetic field. In both cases spinons acquire a charge and hybridize with electrons, producing magnetic oscillations that resemble two-band noninteracting systems. We show that in such band insulators magnetic oscillations are exponentially suppressed at weak magnetic fields. A self-consistent mean-field calculation for the Kondo insulators reveals that the temperature dependence of the oscillations departs from the noninteracting case due to the temperature and magnetic-field dependence of the hybridization, even though mean-field parameters remain homogeneous at low fields. Larger magnetic fields result in the Kondo breakdown, where the magnetic oscillation is solely due to the decoupled conduction electrons. These findings offer new insights into the magnetic properties of Kondo insulators, with implications for interpreting experimental results in heavy fermion materials like SmB$_6$.