Pressure-induced structural transition of double-walled carbon nanotubes

We demonstrate a hydrostatic pressure-induced structure transition of an isolated double-walled carbon nanotube using constant pressure molecular dynamics simulations. We find that, during the transition, the tube cross section is changed from circular to elliptical shape, associated with large reduction of radial bulk modulus. The transition pressure is essentially determined by the inner tube. The van der Waals interaction makes the inner tube and outer tube behave differently.