Temperature-dependent electronic excitations in a 2D graphite layer

The low-frequency electronic excitations of a 2D graphite layer is studied within random-phase approximation. Temperature could induce free carriers and thus significantly changes low-energy excitation properties. There exist intraband and interband single-particle excitations (SPE) and collective excitations. Both intraband SPE and plasmon are purely caused by temperature. Electronic excitations strongly depend on temperature and momentum. The Fermi-momentum state only decay through the intraband e-h excitations. The decay rate of such state quickly grows as temperature increases. A single graphite layer quite differs from a 2D electron gas in electronic excitations and de-excitations.