High-pressure effects on boron nitride multi-walled nanotubes: An X-ray diffraction study

An X-ray diffraction study has been carried out on boron nitride multi-walled nanotubes up to 19.1 GPa. The fit to the unit cell volumes yields a zero pressure bulk modulus K0 = 34.9 ± 1 GPa and its pressure derivative K 0 ′ = 5.9 ± 0.3 . The compression is highly anisotropic, with the intertube-axis being close to 19 times more compressible than the a-axis. At the highest pressure the diffraction peaks were present even though they were weak and broad, which is in contrast to previous high-pressure Raman results.