Structural and electronic properties of BeO nanotubes filled with Cu nanowires

The structural and electronic properties of Cu<Subscript>5-1</Subscript> and Cu<Subscript>6-1</Subscript> nanowires with core-shell structures encapsulated inside a series zigzag (n,0) BeONTs denoted by Cu<Subscript>5-1</Subscript>@(n,0) and Cu<Subscript>6-1</Subscript>@(n,0) are investigated using the first-principles calculations within the generalized-gradient approximation. For Cu<Subscript>5-1</Subscript>@(n,0) (10 ⩽ n ⩽ 17) and Cu<Subscript>6-1</Subscript>@(n,0) (11 ⩽ n ⩽ 18) combined systems, the initial shapes (cylindrical BeONTs and CuNWs) are preserved without any visible change after optimization. The quantum conductances 5G <Subscript>0</Subscript> and 6G <Subscript>0</Subscript> of the most stable Cu<Subscript>5-1</Subscript>@(12,0) and Cu<Subscript>6-1</Subscript>@(13,0) combined systems are identical to the corresponding free-standing Cu<Subscript>5-1</Subscript> and Cu<Subscript>6-1</Subscript> nanowires, respectively. The energy bands crossing the Fermi level in both the Cu<Subscript>5-1</Subscript>@(12,0) and Cu<Subscript>6-1</Subscript>@(13,0) combined systems are all originated from the inner CuNWs. Therefore the electron transport will occur only through the inner CuNWs and the outer inert BeONTs serves well as an insulating cable sheath. The robust quantum conductance of the Cu<Subscript>5-1</Subscript> and Cu<Subscript>6-1</Subscript> nanowires, the insulating protection character of the (12,0) and (13,0) BeONTs and the highest stability of the tube-wire combined systems make the Cu<Subscript>5-1</Subscript>@(12,0) and Cu<Subscript>6-1</Subscript>@(13,0) combined systems are top-priority in the ULSI circuits and MEMS devices that demand steady transport of electrons. Copyright EDP Sciences, SIF, Springer-Verlag Berlin Heidelberg 2013