Abstract
High pressure Raman experiments on boron nitride multi-walled nanotubes show that the intensity of the vibrational mode at ∼1367
cm
−1 vanishes at ∼12
GPa and it does not recover under decompression. In comparison, the high pressure Raman experiments on hexagonal boron nitride show a clear signature of a phase transition from hexagonal to wurtzite at ∼13
GPa which is reversible on decompression. These results are contrasted with the pressure behavior of carbon nanotubes and graphite.