Temperature dependence on transition frequency and energy-levels of longitudinal-acoustic polaron in monolayer graphene under an external field

Abstract

The longitudinal-acoustic (LA) polaron properties in monolayer graphene under an external magnetic field were investigated using Lee-Low-Pines unitary transformation and a linear combination operator. The effects of temperature on the ground state and first excited state (FES) energy, transition frequency, and the mean number of LA phonons were then examined using quantum statistics theory. The results revealed the emergence of a like-bandgap by splitting the energy levels and transition frequency. The like-bandgap was also dependent on the Debye cut-off, magnetic field strength, and temperature, whereas the mean number of LA phonons was increased by magnetic field strength and temperature. Finally, the results demonstrated that changing the system temperature, Debye cut-off wavenumber, and magnetic field strength could control the energy levels, transition frequency, like-bandgap, and several LA phonons.