Unveiling Electron-Phonon Effects on Thermodynamics of Bernal Bilayer Graphene in External Fields

Abstract

We investigate the influence of electron-phonon interactions on the thermodynamic properties of Bernal-stacked bilayer graphene under external magnetic fields, employing the Holstein model and Green’s function approach. By calculating the one-loop electronic self-energy within a full-band framework, we derive the interacting Green’s function to analyze the temperature-dependent behavior of specific heat and Pauli spin susceptibility, alongside the energy-dependent density of states (DOS). Our results reveal that increasing electron-phonon coupling reduces the peak height of specific heat while shifting its characteristic temperature to higher values. Similarly, stronger magnetic fields elevate the DOS at the Fermi level and induce Zeeman splitting, enhancing metallic behavior. Bias voltage variations widen the band gap, reinforcing semiconducting characteristics. These findings highlight the critical role of electron-phonon interactions and external fields in tailoring the electronic and thermodynamic properties of bilayer graphene, offering insights for advanced material applications.