Localization to delocalization transition in a double stranded helical geometry: effects of conformation, transverse electric field and dynamics

Conformational effect on electronic localization is critically investigated for the first time considering a double-stranded helical geometry (DSHG) subjected to an electric field. In the presence of electric field the DSHG behaves like a correlated disordered system whose site potentials are modulated in a cosine form like the well known Aubry–André–Harper model. The potential distribution can be modulated further by changing the orientation of the incident field. A similar kind of cosine modulation is also introduced in the inter-strand hopping integrals of the DSHG. Suitably adjusting the orientation of the electric field, we can achieve fully extended energy eigenstates or completely localized ones or a mixture of both. The effects of short-range and long-range hopping integrals along with the chirality on localization are thoroughly studied. Finally, we inspect the role of helical dynamics to make the model more realistic. The interplay between the helical geometry and electric field may open up several notable features of electronic localization and can be verified by using different chiral molecules. (paper)