Molecular electronics and spintronics provide a promising strategy to overcome limitations of semiconductor-based technologies by implementing electronic functionalities at the molecular scale. However, in order to create single molecule spintronics devices one needs to understand the spin-dependent transport through the molecular system, its dependence on different molecular properties and possible mechanisms to change the magnetization of the molecule. Molecular systems with screw symmetry like DNA are especially interesting for spintronics applications since the transport through these systems can be spin selective [1]. We investigate the eletronic structure of a molecular helix formed by silver atoms and biimidazole units ([Ag(NO₃)(H₂biim)]_n, [2, 3]). First-principles calculations reveal that several molecular orbitals possess screw symmetry and are completely delocalized along the helix. Based on this results we explore the possibility of spin-selective electron transport through this molecular helix.

[1] B. Göhler et al., Science 331, 894 (2011)
[2] C.A. Hester et al., Polyhedron 16, 2893 (1997)
[3] M. Sowwan et al., Journal of Nanomaterials 2010 (2010).