Spin Dependent Transport in Paramagnetic Peapods

The main goal of the project is to incorporate paramagnetic fullerene molecules into single walled carbon nanotubes (SWCNTs) and to study spin-dependent electronic transport in these “peapod” structures. On a fundamental level, peapods provide a well-defined and highly symmetric molecular electronic environment and can be seen as a model system for molecular electronics (Fig. 1). Using the exceptional transport properties of SWCNTs, spin interactions between the guest molecules themselves as well as with their tubular host are experimentally accessible. One the one hand, this opens a way to study the spin-electronic behavior of the hosted molecules, but new insights into the Luttinger liquid behavior of the SWCNT hosts are also expected, i.e. the spin-charge separation of these one-dimensional conductors.

Carbon nanotubes (CNTs) naturally provide a one-dimensional alignment for fullerenes that might be potentially useful, e.g., in quantum computing applications [1]. Little is known about the electronic interaction between fullerenes and CNTs, as few electronic devices have been fabricated yet from peapods. On the other hand, it is possible to confine and manipulate few electrons on a carbon nanotube, using state-of-the-art fabrication technology. Even a single electron and its associated spin in a quantum dot defined on a CNT can now be studied [2]. The combination of this electron control and the nanotube filling, especially with paramagnetic impurities, provides a new architecture for spintronic devices.
 
[1] Architectures for a spin quantum computer based on endohedral fullerenes
W. Harneit, C. Meyer, A. Weidinger, D. Suter, J. Twamley
physica status solidi (b) 233, No. 3, 453-461 (2002)
 
[2] Electron–hole symmetry in a semiconducting carbon nanotube quantum dot
P. Jarillo-Herrero, S. Sapmaz, C. Dekker, L.P. Kouwenhoven, H.S.J. van der Zant
Nature 429, 389 (2004)