Krusin-Elbaum L, Newns D M, Zeng H, Derycke V, Sun J Z, Sandstrom R
IBM Research Division, T. J. Watson Research Center, Yorktown Heights, New York 10598, USA.
Nature. 2004 Oct 7;431(7009):672-6. doi: 10.1038/nature02970.
Nanotubes and nanowires with both elemental (carbon or silicon) and multi-element compositions (such as compound semiconductors or oxides), and exhibiting electronic properties ranging from metallic to semiconducting, are being extensively investigated for use in device structures designed to control electron charge. However, another important degree of freedom--electron spin, the control of which underlies the operation of 'spintronic' devices--has been much less explored. This is probably due to the relative paucity of nanometre-scale ferromagnetic building blocks (in which electron spins are naturally aligned) from which spin-polarized electrons can be injected. Here we describe nanotubes of vanadium oxide (VO(x)), formed by controllable self-assembly, that are ferromagnetic at room temperature. The as-formed nanotubes are transformed from spin-frustrated semiconductors to ferromagnets by doping with either electrons or holes, potentially offering a route to spin control in nanotube-based heterostructures.
具有元素组成（碳或硅）和多元素组成（如化合物半导体或氧化物）、且展现出从金属性到半导体性等多种电子特性的纳米管和纳米线，正被广泛研究用于旨在控制电子电荷的器件结构中。然而，另一个重要的自由度——电子自旋，其控制是“自旋电子学”器件运行的基础——却很少被探索。这可能是由于可用于注入自旋极化电子的纳米级铁磁构建块（其中电子自旋自然排列）相对较少。在此，我们描述了通过可控自组装形成的室温下具有铁磁性的氧化钒（VO(x)）纳米管。所形成的纳米管通过电子或空穴掺杂从自旋受挫半导体转变为铁磁体，这可能为基于纳米管的异质结构中的自旋控制提供一条途径。
