Abstract
We report a sharp band observed at 867 in polarized Raman scattering from the edge plane of highly oriented pyrolytic graphite (HOPG). Polarization measurements indicates that this band is a vibrational mode with “out-of-plane” atomic displacement which is absolutely unexpected from the factor-group analysis. This band can be assigned to the zone-center mode originating from the Raman-inactive mode which becomes Raman active by modification of crystalline point-group symmetry due to a slight rearrangement of lattice structure at the edge. The origin of the band is fundamentally different from that for the 1355- and bands (D, band) which are peculiar to disordered graphite and are modes becoming Raman active due to the breakdown of the wave-vector selection rule by loss of translational symmetry.
- Received 23 April 1998
DOI:https://doi.org/10.1103/PhysRevB.59.62
©1999 American Physical Society