Structure and transport characteristics of modified DNA with magnetic ions

Abstract

Motivated by recent experiments we study the alignment of magnetic ions Cu²⁺ and Mn²⁺ along the modified DNA helix. We find that doping with magnetic ions induces conducting states in the gap region of natural DNA. These magnetic ions are found to interact ferromagnetically along the DNA helix. Calculations of optical conductivity about the helical axis suggest that the origin of magnetic characteristics depend on the metal ions; while Cu-DNA favors in-plane σ-like delocalization over the base pairs, the Mn-DNA favors out-of-plane (π) delocalizations. Such an alignment of magnetic ions offers promising perspectives for creating low-dimensional polarized spin channel within the DNA helix.