Heat capacity of hexagonal boron nitride sheet in Holstein model

The effects of electron-phonon interaction on the electronic heat capacity of hexagonal boron nitride plane are investigated within the Holstein Hamiltonian model and Green's function formalism. By using different electron-phonon coupling constants of boron and nitrogen sublattices, it is found that the specific heat has different behaviors in two temperature regions. In the low temperature region, the electron-phonon interaction causes the enhancement of specific heat due to decreasing the band gap, while heat capacity reduces in the high temperature region because of decreasing the excitation spectrum.