Structural and electronic properties of SiC nanotubes filled with Cu nanowires: A first-principles study

The structural and electronic properties of Cu (n=5,9,13) nanowires encapsulated in armchair (8,8) silicon carbon nanotubes (SiCNTs) are investigated using the first principles calculations within the generalized-gradient approximation. We find that the formation processes of these systems are all exothermic. The initial shapes (quadratic-prismatic Cu wire and cylindrical (8,8) SiCNT) are preserved without any visible changes after optimization for the Cu-5@(8,8) and Cu-9@(8,8) combined systems, but a quadratic-like cross-section shape is formed for the outer nanotube of the Cu-13@(8,8) combined system due to the stronger interaction between nanowire and nanotube. The electrons for Si and C atoms in outer SiC sheath affect the electron conductance of the encapsulated metallic nanowire in the Cu-13@(8,8) combined system. But in the Cu-5@(8,8) and Cu-9@(8,8) combined systems, the conduction electrons are distributed only on the copper atoms, so electron transport will occur only through the inner Cu nanowires and the outer inert SiCNTs only function as insulating cable sheaths. Considering the maximal metal filling ratio in nanotube, we know that the Cu-9@(8,8) combined system is top-priority in the ultra-large-scale integration (ULSI) circuits and micro-electromethanical systems (MEMS) devices that demand steady transport of electrons. (C) 2013 Elsevier B.V. All rights reserved.