By using the first-principles calculations based on the density functional theory, the structural and electronic properties of pentagonal Cu nanowires encapsulated in a series of zigzag (n,0) BNNTs have been systematically investigated. The initial shapes (cylindrical CuNWs and BNNTs) are preserved without any visible changes for the CuNW@(n,0) combined systems. The most stabile combined system is CuNW@(14,0) with an optimal tube-wire distance of about 0.34 nm and a simple superposition of the band structures of it′s components (CuNW and (14,0) BNNT) near the Fermi level. A quantum conductance of 4G0 is obtained for both CuNW in either free-standing state or filled into BNNT. The charge density analyses also show that the electron transport will occur only through the inner CuNW and the inert outer BNNT serves well as insulating cable sheath. So the CuNW@(14,0) combined system is top-priority in the ultra-large-scale integration (ULSI) circuits and micro-electromechanical systems (MEMS) devices that demand steady transport of electrons.

Cu nanowires; boron nitride nanotubes; relaxed structures; electronic property; first-principles