Raman spectroscopy on single- and multi-walled nanotubes under high pressure

The pressure dependence of the high-energy Raman modes in single- and multi -walled carbon nanotubes was measured in the range 0-10 GPa. We found the p ressure coefficient to be linear in both materials but 25% smaller in MWNT. Given that the curvature effects on vibrational properties of the rolled-u p graphene sheets are small, we can explain this difference simply with ela sticity theory.