Temperature-dependent Raman spectra and anomalous Raman phenomenon of highly oriented pyrolytic graphite

The Stokes and anti-Stokes Raman spectra of the pristine and ion-implanted highly oriented pyrolytic graphite (HOPG) are reported. For all Raman bands, noticeable frequency shifts are observed in the different temperature of samples. The anomalous Raman phenomenon (ARP) indicates that some modes occurring on the Stokes and anti-Stokes sides have different frequencies for HOPG. The data suggest that the ARP is closely related with the excitation wavelength (lambda) dependence of Raman bands of the graphite. According to the temperature effect and the ARP, we assign and verify some modes of HOPG, and predict some new results.