525070.fig.003
Figure 3: Diameter dependence of phononic bandgaps of zigzag-CNTs with chirality from to . Dots show phononic bandgaps from the phonon bands, and crosspoints show those by the zone-folding method. Blue colors are phononic bandgaps where is the multiple of , red colors are those where is the sum of multiples of and , and black colors are those where is the sum of multiple of and .