▎ 摘　　要

Intensities of the first-and the second-order Raman spectra are calculated as a function of the Fermi energy. We show that the Kohn anomaly effect, i.e., phonon frequency renormalization, in the first-order Raman spectra originates from the phonon renormalization by the interband electron-hole excitation, whereas in the second-order Raman spectra, a competition between the interband and intraband electron-hole excitations takes place. By this calculation, we confirm the presence of different dispersive behaviors of the Raman peak frequency as a function of the Fermi energy for the first-and the second-order Raman spectra, as observed in some previous experiments. Moreover, the calculated results of the Raman intensity sensitively depend on the Fermi energy for both the first-and the second-order Raman spectra, indicating the presence of the quantum interference effect. The electron-phonon matrix element plays an important role in the intensity increase ( decrease) of the combination ( overtone) phonon modes as a function of the Fermi energy.