▎ 摘　　要

We present the quantum entanglement and the thermal entanglement in a graphene layer. The model Hamiltonian is chosen within an effective-mass approximation, including the interaction of intervalley and intravalley scattering processes. We find that the degenerate ground state is unentangled and that the thermal concurrence decreases down to zero as the temperature increases. A new maximally entangled quantum state is observed from the excited states of the system by using a proper choice of the Hamiltonian parameters.