One-dimensional alkali-doped C₆₀ chains encapsulated in BN nanotubes

We study the energetics, electronic structures, and electron-phonon couplings of a one-dimensional potassium-doped C₆₀ chain encapsulated in a boron nitride nanotube using the framework of the density-functional theory. We demonstrate that the reaction of potassium doping is exothermic and the resulting material is one-dimensional metal where conducting electrons are only in the C₆₀ chain. Interestingly, the Fermi-level density of states has a peculiar pressure dependence and can be larger than those in the three-dimensional alkali-doped fullerene compounds, indicating the possibility of various phase transitions. We also discuss the electron-phonon couplings and the possibility of superconductivity.