Helical Molecule as an Efficient Rectifier: Effects of Molecular Conformation and Transverse Electric Field

Abstract

The phenomenon of charge current rectification is critically investigated using a single stranded helical molecule in presence of transverse electric field. Two different helical molecules, DNA and protein, are taken into account to explore the specific roles of molecular conformation on rectification, which have not been addressed so far to the best of our concern. Sandwiching the molecular system within source and drain electrodes, we compute charge currents for two bias polarities and the degree of current rectification based on nonequilibrium Green's function formalism within a tight-binding framework. At non-zero electric field, site energies of the molecule are modulated in a cosine form, similar to the well known Aubry-André-Harper relation, resulting an atypical and fragmented energy band spectrum. The appearance of nonuniform site energies plays the central role for generating different currents in two bias polarities, and thus, the current rectification. We find that a high degree of current rectification can be established using the helical system and it becomes more effective for the protein molecule than the DNA one. At the end, the rectification operation considering a more general helical structure is discussed to make the present communication a self-contained one. Our proposition may provide a new route of getting controlled current rectification using similar kind of biological molecules and other tailor made helical geometries.

Spin-selective thermoelectric transport along a vibrating α-helical protein molecule

“…Our Hamiltonian and method can be extended to deal with any quasi-1D molecular transport containing SOI. The spin filtering of quasi-1D non-magnetic systems is a very promising subject, for example, transverse electric field may result in an obvious rectification effect on spin filtering of α-helical protein molecules [48]. Spin-polarization of current can be the fingerprint to identify whether the transport is driven by the electric bias or the thermal bias, which worth the wait in the field of bio-thermoelectricity and spin caloritronics.…”