Benzimidazole-modified single-stranded DNA: stable scaffolds for 1-dimensional spintronics constructs

Abstract

We investigate the electronic and magnetic properties of the proposed one-dimensional TM_n(benzimidazole)_n+1 (TM = Sc, Ti, V, Cr, Mn) systems by means of density functional theory. We find that the rigid benzimidazole (Bzim) scaffold can stabilize the Ti, V, and Cr transition metal (TM) atoms, while still retaining the helical and one-dimensional characteristics of DNA. The strong coupling between the TM d-orbitals and the HOMO, HOMO-1, and LUMO orbitals of Bzim are found to govern the electronic and magnetic properties of these systems. Under the application of an external electric field, a robust half-metallic behavior is predicted for the V₈(Bzim)₉ system, which is traced back to the pinning of certain orbitals in the presence of an external field. The ease of attaching a thiol linker to the 5' and 3' ends of the DNA strands and formation of stable self-assembled monolayers (SAM) of DNA on metal substrates make these TM_n(Bzim)_n+1 DNA constructs promising materials for advanced spintronics applications.