▎ 摘　　要

In the present work, we consider an electron strongly coupled with in-plane longitudinal acoustic (LA) phonons in monolayer graphene under an external magnetic field. The ground state energy (GSE) and the LA phonons' mean number are investigated as function of temperature, cut-off wavenumber and magnetic field using the quantum statistical theory (QST). It is found that the GSE of the magnetopolamn in monolayer graphene splits into two branches. The GSE and the LA mean phonon number increase with elevated temperature and are both an increasing function of the cut-off wavenumber and magnetic field.