One-dimensional Metallic Peanut-shaped Nanocarbon with Positive and Negative Gaussian Curvatures : Toward a New Science of Quantum Electronic Systems on Riemannian Surface

摘要

When a C_(60) film is irradiated with a 3 kV electron-beam (EB) gun in vacuum (base pressure : 10~(-7) Pa), we have found that EB-irradiation of a C_(60) film gives rise to formation of a peanut-shaped C_(60) polymer with metallic electron-transport properties in air at room temperature. The peanut-shaped polymer has both positive and negative Gaussian curvatures (K), which can be classified into a new π-electron conjugated carbon allotrope that is different from graphite (K=0), fullerenes (K>0), nanotubes (K = 0 at body, K>0 at cap edge), and hypothetical Mackay crystal (K<0). In the present review article, we will introduce our recent results of the electron-transport, electronic, and optical properties of the nanocarbon, and describe theoretical analysis of its novel electronic properties on the basis of quantum mechanics on Riemannian surfaces. To our best knowledge, the peanut-shaped C_(60) polymer is only an existed material with a negative Gaussian curvature, whose electronic and optical properties are known experimentally. Thus we believe that the present system will open a new science "quantum science of condensed matters in Riemannian space".peanut-shaped nanocarbon;;Gaussian curvature;;Tomonaga-Luttinger liquids;;Peierls instability;;quantum mechanics on Riemannian surface