Effects of inter wall hopping on the electronic properties of double-wall carbon nanotubes

We study effects of changing inter wall hopping on the electronic and structural properties of (n,n)@(2n,2n)(n,n)@(2n,2n) and (n,0)@(2n,0)(n,0)@(2n,0) double-wall carbon nanotubes using tight-binding model. We found by switching inter-wall interactions a valley opened in the (n,n)@(2n,2n)(n,n)@(2n,2n) local density of states, although both walls remained metallic. For the case of (n,0)@(2n,0)(n,0)@(2n,0) where nnis not multiple of   3 a semiconducting to metallic phase transition is found, while when nnis multiple of 3 both inner and outer walls remained metallic.