Semiconducting cyanide-transition-metal nanotubes.

We propose a new type of structurally simple and energetically stable cyanide-transition-metal nanotube, based on the planar structure of M(CN)2, (M = Ni, Pd, Pt). These nanotubes have a semiconducting character with a large bandgap (2-3 eV) that is insensitive to chirality and diameter. The energetic, electronic, and mechanical properties of these materials in both planar and tubular forms are studied through first-principles density functional theory calculations. The calculations reveal interesting multicenter bonding features, which should lead to preferential growth of tubes of a particular chirality. These intrinsically semiconducting nanotubes can be readily p- or n-doped, which makes them good candidates for nanoscale elements in electronic devices.