  Non-dispersive, inter-layer interaction induced Raman peaks (I bands) -- in
the region of the D band -- have been observed recently for bilayer graphene,
when the two layers were rotated with respect to each other. Here, similar
observations for double-walled carbon nanotubes (DWCNTs) are theoretically
predicted. The prediction is based on double resonance theory, involving
non-zone-centered phonons, and the effect of disorder is replaced by
interaction between the two tubes.
